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Lizhong Xiong - One of the best experts on this subject based on the ideXlab platform.
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feedback regulation of aba signaling and biosynthesis by a bzip transcription factor targets Drought Resistance related genes
Plant Physiology, 2016Co-Authors: Wei Zong, Ning Tang, Jun Yang, Lei Peng, Lizhong XiongAbstract:The OsbZIP23 transcription factor has been characterized for its essential role in Drought Resistance in rice (Oryza sativa), but the mechanism is unknown. In this study, we first investigated the transcriptional activation of OsbZIP23. A homolog of SnRK2 protein kinase (SAPK2) was found to interact with and phosphorylate OsbZIP23 for its transcriptional activation. SAPK2 also interacted with OsPP2C49, an ABI1 homolog, which deactivated the SAPK2 to inhibit the transcriptional activation activity of OsbZIP23. Next, we performed genome-wide identification of OsbZIP23 targets by immunoprecipitation sequencing and RNA sequencing analyses in the OsbZIP23-overexpression, osbzip23 mutant, and wild-type rice under normal and Drought stress conditions. OsbZIP23 directly regulates a large number of reported genes that function in stress response, hormone signaling, and developmental processes. Among these targets, we found that OsbZIP23 could positively regulate OsPP2C49, and overexpression of OsPP2C49 in rice resulted in significantly decreased sensitivity of the abscisic acid (ABA) response and rapid dehydration. Moreover, OsNCED4 (9-cis-epoxycarotenoid dioxygenase4), a key gene in ABA biosynthesis, was also positively regulated by OsbZIP23. Together, our results suggest that OsbZIP23 acts as a central regulator in ABA signaling and biosynthesis, and Drought Resistance in rice.
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general mechanisms of Drought response and their application in Drought Resistance improvement in plants
Cellular and Molecular Life Sciences, 2015Co-Authors: Yujie Fang, Lizhong XiongAbstract:Plants often encounter unfavorable environmental conditions because of their sessile lifestyle. These adverse factors greatly affect the geographic distribution of plants, as well as their growth and productivity. Drought stress is one of the premier limitations to global agricultural production due to the complexity of the water-limiting environment and changing climate. Plants have evolved a series of mechanisms at the morphological, physiological, biochemical, cellular, and molecular levels to overcome water deficit or Drought stress conditions. The Drought Resistance of plants can be divided into four basic types-Drought avoidance, Drought tolerance, Drought escape, and Drought recovery. Various Drought-related traits, including root traits, leaf traits, osmotic adjustment capabilities, water potential, ABA content, and stability of the cell membrane, have been used as indicators to evaluate the Drought Resistance of plants. In the last decade, scientists have investigated the genetic and molecular mechanisms of Drought Resistance to enhance the Drought Resistance of various crops, and significant progress has been made with regard to Drought avoidance and Drought tolerance. With increasing knowledge to comprehensively decipher the complicated mechanisms of Drought Resistance in model plants, it still remains an enormous challenge to develop water-saving and Drought-resistant crops to cope with the water shortage and increasing demand for food production in the future.
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conserved mir164 targeted nac genes negatively regulate Drought Resistance in rice
Journal of Experimental Botany, 2014Co-Authors: Yujie Fang, Kabin Xie, Lizhong XiongAbstract:MicroRNAs constitute a large group of endogenous small RNAs of ~22 nt that emerge as vital regulators, mainly by targeting mRNAs for post-transcriptional repression. Previous studies have revealed that the miR164 family in Arabidopsis is comprised of three members which guide the cleavage of the mRNAs of five NAC genes to modulate developmental processes. However, the functions of the miR164-targeted NAC genes in crops are poorly deciphered. In this study, the conserved features of six miR164-targeted NAC genes (OMTN1-OMTN6) in rice are described, and evidence is provided that four of them confer a negative regulatory role in Drought Resistance. OMTN proteins have the characteristics of typical NAC transcriptional factors. The miR164 recognition sites of the OMTN genes are highly conserved in rice germplasms. Deletion of the recognition sites impaired the transactivation activity, indicating that the conserved recognition sites play a crucial role in maintaining the function of the OMTN proteins. The OMTN genes were responsive to abiotic stresses, and showed diverse spatio-temporal expression patterns in rice. Overexpression of OMTN2, OMTN3, OMTN4, and OMTN6 in rice led to negative effects on Drought Resistance at the reproductive stage. The expression of numerous genes related to stress response, development, and metabolism was altered in OMTN2-, OMTN3-, OMTN4-, and OMTN6-overexpressing plants. Most of the up-regulated genes in the OMTN-overexpressing plants were down-regulated by Drought stress. The results suggest that the conserved miR164-targeted NAC genes may be negative regulators of Drought tolerance in rice, in addition to their reported roles in development.
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evaluation of near isogenic lines for Drought Resistance qtl and fine mapping of a locus affecting flag leaf width spikelet number and root volume in rice
Theoretical and Applied Genetics, 2011Co-Authors: Xipeng Ding, Xiaokai Li, Lizhong XiongAbstract:Drought stress is a major limiting factor for crop production and breeding for Drought Resistance is very challenging due to the complex nature of this trait. Previous studies in rice suggest that the upland japonica variety IRAT109 shows better Drought Resistance than the lowland indica variety Zhenshan 97. Numerous quantitative trait loci (QTL) have been previously mapped using a recombinant inbred line population derived from these two genotypes. In this study, near-isogenic lines (NILs) for 17 Drought Resistance-related QTL were constructed and phenotypic variations of these NILs were investigated under Drought and normal conditions. Fourteen of these NILs showed significant phenotypic differences relative to the recurrent parent under at least one of the conditions and nine NILs showed significant differences under both conditions. After eliminating the effect of heading date on Drought Resistance, only four NILs carrying seven QTL (four for the same grain yield-related traits and three for the same or similar root traits QTL) showed differences consistent with the original QTL mapping results. One of these lines (N19) contains qFSR4, a QTL on chromosome 4 controlling root volume per tiller and co-segregating with flag leaf width and spikelet number per panicle. Using a population derived from N19, qFSR4 was mapped to a 38-kb region containing three open reading frames including the previously characterized NARROW LEAF 1 (NAL1) gene. NAL1, which controls leaf width and also affects vein patterning and polar auxin transport, is the most promising candidate genes for qFSR4. Our results underscore the importance of the development of NILs to confirm the identification of QTL affecting complex traits such as Drought Resistance.
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evaluation of near isogenic lines for Drought Resistance qtl and fine mapping of a locus affecting flag leaf width spikelet number and root volume in rice
Theoretical and Applied Genetics, 2011Co-Authors: Xipeng Ding, Lizhong XiongAbstract:Drought stress is a major limiting factor for crop production and breeding for Drought Resistance is very challenging due to the complex nature of this trait. Previous studies in rice suggest that the upland japonica variety IRAT109 shows better Drought Resistance than the lowland indica variety Zhenshan 97. Numerous quantitative trait loci (QTL) have been previously mapped using a recombinant inbred line population derived from these two genotypes. In this study, near-isogenic lines (NILs) for 17 Drought Resistance-related QTL were constructed and phenotypic variations of these NILs were investigated under Drought and normal conditions. Fourteen of these NILs showed significant phenotypic differences relative to the recurrent parent under at least one of the conditions and nine NILs showed significant differences under both conditions. After eliminating the effect of heading date on Drought Resistance, only four NILs carrying seven QTL (four for the same grain yield-related traits and three for the same or similar root traits QTL) showed differences consistent with the original QTL mapping results. One of these lines (N19) contains qFSR4, a QTL on chromosome 4 controlling root volume per tiller and co-segregating with flag leaf width and spikelet number per panicle. Using a population derived from N19, qFSR4 was mapped to a 38-kb region containing three open reading frames including the previously characterized NARROW LEAF 1 (NAL1) gene. NAL1, which controls leaf width and also affects vein patterning and polar auxin transport, is the most promising candidate genes for qFSR4. Our results underscore the importance of the development of NILs to confirm the identification of QTL affecting complex traits such as Drought Resistance.
S Fukai - One of the best experts on this subject based on the ideXlab platform.
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associations between Drought Resistance regrowth and quality in a perennial c4 grass
European Journal of Agronomy, 2015Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Abstract Climate change has brought a sharp and renewed focus on plant breeding programs to develop cultivars with improved performance in dry environments. The pleiotropic effects of selection for Drought Resistance are not well understood in perennial C 4 grasses. The objective of this study was to determine the commercial production characteristics including sod strength and post-harvest regrowth of bermudagrass ecotypes selected for Drought Resistance. These attributes were studied in a set of bermudagrasses ( Cynodon dactylon ), a species used extensively around the world for forage and turfgrass. Three field experiments using 12 genotypes contrasting for Drought Resistance were evaluated, on bermudagrass turf production facilities, for quality and regrowth after the canopy (sod) was mechanically removed. Among the genotypes tested, there was large genotypic variation for rhizome dry matter (RhDM) (0.01–0.81 kg m −2 ), aboveground dry matter (ADM) (0.59–0.17 kg m −2 ) and root dry matter (RDM) (0.04–0.12 kg m −2 ). Regrowth of the canopy was positively correlated to RhDM (r = 0.79∼0.80) and negatively correlated to ADM (r = −0.69∼−0.74) but there was no association with RDM. Biomass partitioning determined at the time of the second harvest revealed that genotypes with more rapid regrowth had larger proportional DM distributed to rhizome (63.5% vs 7.1%) than to aboveground (27.2% vs 86.5%) and root (8.5% vs 8.1%). Our previous research with these genotypes showed a strong correlation between Drought Resistance and RhDM prior to the Drought period. Consequently, an analysis of the relationship between Drought Resistance measured previously and post-harvest regrowth in the experiments described here revealed a strong positive correlation (r > 0.64). Genotypic variation for sod strength, an important turf quality attribute, was large ranging from 1281 kg m −2 to 5671 kg m −2 . However, sod strength was neither correlated to Drought Resistance, nor the traits measured from harvested sod such as stolon diameter, internode length, number of branches and single stolon strength, nor to dry matter distribution. These results may reflect the existence of a range of different mechanisms for sod strength present in the material tested. Nevertheless, there were genotypes e.g., MED1 that combined the favorable traits of Drought Resistance, faster regrowth rate and higher sod strength and could be used as an important genetic resource for future breeding. MED1 was one of several highly rhizomatous genotypes in the study that originated from the Mediterranean climatic zone of Australia.
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Drought Resistance and soil water extraction of a perennial c4 grass contributions of root and rhizome traits
Functional Plant Biology, 2014Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Previously, we showed that genotypic differences in soil water extraction were associated with Drought response, but we did not study underground root and rhizome characteristics. In this study, we demonstrate a similar relationship between Drought Resistance and soil water extraction but investigate the role of underground organs. Eighteen bermudagrass genotypes (Cynodon spp.) from four climatic zones were assessed under continuous Drought at two locations with contrasting soils and climates. The criterion for Drought Resistance was the duration required to reach 50% green cover (GC50) after water was withheld. GC50, physiological traits, rhizome dry matter (RhDM), root length density (RLD) and average root diameter (ARD) were determined in both locations; water extraction was measured in one location. Large genotypic variation for Drought Resistance was observed in both locations, with GC50 being 187-277 days in a clay soil and 15-27 days in a sandy soil. Drought-resistant genotypes had greater soil water extraction and a higher water uptake rate. GC50 was correlated with relative water content (r=0.76), canopy temperature differential (r=-0.94) and photosynthetic rate (r=0.87) measured during Drought; RhDM (r=0.78 to ~0.93) before and after Drought; and ARD after Drought (r=0.82 to ~0.94); GC50 was not correlated with RLD. Ecotypes collected from the Australian Mediterranean zone had superior Drought Resistance and were characterised by a large rhizome network. This is the first comprehensive study with perennial C4 grasses describing the association between water extraction, root distribution, rhizomes and Drought Resistance.
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Drought Resistance of c4 grasses under field conditions genetic variation among a large number of bermudagrass cynodon spp ecotypes collected from different climatic zones
Journal of Agronomy and Crop Science, 2013Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Predictions of extreme weather resulting from climate change will present huge challenges for scientists trying to maintain and increase agricultural production. A greater frequency of dry periods is predicted placing emphasis on the development of plant varieties that are able to maintain performance in dry conditions. The aim of this research was to determine the genetic variation for Drought Resistance among a large range of potential pasture or turf bermudagrasses (Cynodon spp.). Four hundred and sixty genotypes including ecotypes collected from different climatic zones of Australia, and commercial cultivars were established in the field and assessed during natural and imposed Drought periods. Using descriptors of Drought Resistance such as turf quality and green cover, genotypes were classified into different groups; 436 genotypes were clustered into ten groups in one experiment, and 72 genotypes were clustered into three groups in a second. There was a high correlation of response (r = 0.78) for 47 genotypes common to both experiments suggesting that the Drought Resistance techniques used to group genotypes were robust. Physiological analyses of the genotypes within the superior Drought Resistance groups indicated that these group members were probably able to extract more available soil water during the Drought period. No commercial cultivars were found in the most Drought Resistance groups. These field studies also suggested that future collections of bermudagrass ecotypes designed to select for Drought Resistance might best be carried out from regions that experience Mediterranean climates. The field evaluations presented here did not correlate well with Drought Resistance determined in previously reported shallow lysimeter (40 cm deep) experiments.
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Drought Resistance of bermudagrass cynodon spp ecotypes collected from different climatic zones
Environmental and Experimental Botany, 2013Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Abstract The objectives of this paper were to (1) evaluate Drought Resistance of a large number of bermudagrass ecotypes collected from different climatic zones of regional Australia and compare their performance to commercial cultivars, (2) describe the mechanisms of Drought Resistance observed, and (3) investigate the relationship between geographic origins of the ecotypes and their Drought Resistance. Fifty-two genotypes of bermudagrass were evaluated in two field experiments using lysimeters 40 cm deep. The grasses were grown in well-watered conditions and then a Drought treatment was imposed by withholding water and excluding rainfall using a portable rain-out shelter. Two criteria were used to select for Drought Resistance, i.e. survival period (SP), defined as the number of days after water was withheld to the stage when 100% leaf firing had occurred and Days 50 defined as the days required to reach 50% green cover. These experiments suggested that genotypes with superior Drought Resistance had lower stomatal conductance in the earlier phases of the dry-down period as suggested by less water use and higher canopy temperature depression. Lower water use during the early stage of dry-down resulted in more soil available water at the end of the Drought period to extend green-leaf cover. There was no correlation between root dry matter and survival period/Days 50 . We also found some ecotypes performed better in Drought conditions than popular commercial cultivars. There was no relationship between Drought Resistance and geographic origins, suggesting that Drought resistant ecotypes could be obtained from any climatic zone sampled in this study.
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phenotypic and genotypic analysis of Drought Resistance traits for development of rice cultivars adapted to rainfed environments
Field Crops Research, 2008Co-Authors: Akihiko Kamoshita, Chandra R Babu, Manikanda N Boopathi, S FukaiAbstract:Abstract Many of the world's rice-growing regions lack adequate irrigation facilities, and Drought frequently reduces yield. This paper reviews Drought-Resistance traits in rice and their quantitative trait loci (QTLs), with emphasis on CT9993/IR62266, one of the most widely studied mapping populations, and suggests ways to develop cultivars that will perform well in Drought-prone environments. Information about the type of Drought faced in the target region – particularly the timing of the Drought (late season terminal Drought, early stage vegetative Drought, and intermittent Drought) and the intensity of the Drought – are important in determining the specific plant traits required to improve Drought Resistance in rice. Most of these traits are related to Drought avoidance strategy, so that the Drought-resistant genotypes are able to maintain better internal water status, either by taking up more water through a better root system or by reducing the rate of plant water use. We identified and listed a number of QTLs for many Drought-Resistance traits, such as deep roots. We identified four key genomic regions on chromosomes 1, 4, 8, and 9 on which are co-located a number of QTLs for traits considered to be directly or indirectly responsible for grain yield under stress. These regions, once they have been more finely mapped, appear promising for eventual use in marker-assisted selection for development of Drought-resistant rice varieties. In addition to selecting for specific traits or specific genomic regions, screening under managed Drought conditions on the basis of yield itself or on spikelet fertility adjusted for flowering time appears useful, because of the relatively high degrees of heritability of these characters, for the development of Drought-resistant rice cultivars, and it is currently practiced in some breeding programs.
Xipeng Ding - One of the best experts on this subject based on the ideXlab platform.
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evaluation of near isogenic lines for Drought Resistance qtl and fine mapping of a locus affecting flag leaf width spikelet number and root volume in rice
Theoretical and Applied Genetics, 2011Co-Authors: Xipeng Ding, Xiaokai Li, Lizhong XiongAbstract:Drought stress is a major limiting factor for crop production and breeding for Drought Resistance is very challenging due to the complex nature of this trait. Previous studies in rice suggest that the upland japonica variety IRAT109 shows better Drought Resistance than the lowland indica variety Zhenshan 97. Numerous quantitative trait loci (QTL) have been previously mapped using a recombinant inbred line population derived from these two genotypes. In this study, near-isogenic lines (NILs) for 17 Drought Resistance-related QTL were constructed and phenotypic variations of these NILs were investigated under Drought and normal conditions. Fourteen of these NILs showed significant phenotypic differences relative to the recurrent parent under at least one of the conditions and nine NILs showed significant differences under both conditions. After eliminating the effect of heading date on Drought Resistance, only four NILs carrying seven QTL (four for the same grain yield-related traits and three for the same or similar root traits QTL) showed differences consistent with the original QTL mapping results. One of these lines (N19) contains qFSR4, a QTL on chromosome 4 controlling root volume per tiller and co-segregating with flag leaf width and spikelet number per panicle. Using a population derived from N19, qFSR4 was mapped to a 38-kb region containing three open reading frames including the previously characterized NARROW LEAF 1 (NAL1) gene. NAL1, which controls leaf width and also affects vein patterning and polar auxin transport, is the most promising candidate genes for qFSR4. Our results underscore the importance of the development of NILs to confirm the identification of QTL affecting complex traits such as Drought Resistance.
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evaluation of near isogenic lines for Drought Resistance qtl and fine mapping of a locus affecting flag leaf width spikelet number and root volume in rice
Theoretical and Applied Genetics, 2011Co-Authors: Xipeng Ding, Lizhong XiongAbstract:Drought stress is a major limiting factor for crop production and breeding for Drought Resistance is very challenging due to the complex nature of this trait. Previous studies in rice suggest that the upland japonica variety IRAT109 shows better Drought Resistance than the lowland indica variety Zhenshan 97. Numerous quantitative trait loci (QTL) have been previously mapped using a recombinant inbred line population derived from these two genotypes. In this study, near-isogenic lines (NILs) for 17 Drought Resistance-related QTL were constructed and phenotypic variations of these NILs were investigated under Drought and normal conditions. Fourteen of these NILs showed significant phenotypic differences relative to the recurrent parent under at least one of the conditions and nine NILs showed significant differences under both conditions. After eliminating the effect of heading date on Drought Resistance, only four NILs carrying seven QTL (four for the same grain yield-related traits and three for the same or similar root traits QTL) showed differences consistent with the original QTL mapping results. One of these lines (N19) contains qFSR4, a QTL on chromosome 4 controlling root volume per tiller and co-segregating with flag leaf width and spikelet number per panicle. Using a population derived from N19, qFSR4 was mapped to a 38-kb region containing three open reading frames including the previously characterized NARROW LEAF 1 (NAL1) gene. NAL1, which controls leaf width and also affects vein patterning and polar auxin transport, is the most promising candidate genes for qFSR4. Our results underscore the importance of the development of NILs to confirm the identification of QTL affecting complex traits such as Drought Resistance.
Yi Zhou - One of the best experts on this subject based on the ideXlab platform.
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associations between Drought Resistance regrowth and quality in a perennial c4 grass
European Journal of Agronomy, 2015Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Abstract Climate change has brought a sharp and renewed focus on plant breeding programs to develop cultivars with improved performance in dry environments. The pleiotropic effects of selection for Drought Resistance are not well understood in perennial C 4 grasses. The objective of this study was to determine the commercial production characteristics including sod strength and post-harvest regrowth of bermudagrass ecotypes selected for Drought Resistance. These attributes were studied in a set of bermudagrasses ( Cynodon dactylon ), a species used extensively around the world for forage and turfgrass. Three field experiments using 12 genotypes contrasting for Drought Resistance were evaluated, on bermudagrass turf production facilities, for quality and regrowth after the canopy (sod) was mechanically removed. Among the genotypes tested, there was large genotypic variation for rhizome dry matter (RhDM) (0.01–0.81 kg m −2 ), aboveground dry matter (ADM) (0.59–0.17 kg m −2 ) and root dry matter (RDM) (0.04–0.12 kg m −2 ). Regrowth of the canopy was positively correlated to RhDM (r = 0.79∼0.80) and negatively correlated to ADM (r = −0.69∼−0.74) but there was no association with RDM. Biomass partitioning determined at the time of the second harvest revealed that genotypes with more rapid regrowth had larger proportional DM distributed to rhizome (63.5% vs 7.1%) than to aboveground (27.2% vs 86.5%) and root (8.5% vs 8.1%). Our previous research with these genotypes showed a strong correlation between Drought Resistance and RhDM prior to the Drought period. Consequently, an analysis of the relationship between Drought Resistance measured previously and post-harvest regrowth in the experiments described here revealed a strong positive correlation (r > 0.64). Genotypic variation for sod strength, an important turf quality attribute, was large ranging from 1281 kg m −2 to 5671 kg m −2 . However, sod strength was neither correlated to Drought Resistance, nor the traits measured from harvested sod such as stolon diameter, internode length, number of branches and single stolon strength, nor to dry matter distribution. These results may reflect the existence of a range of different mechanisms for sod strength present in the material tested. Nevertheless, there were genotypes e.g., MED1 that combined the favorable traits of Drought Resistance, faster regrowth rate and higher sod strength and could be used as an important genetic resource for future breeding. MED1 was one of several highly rhizomatous genotypes in the study that originated from the Mediterranean climatic zone of Australia.
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Drought Resistance and soil water extraction of a perennial c4 grass contributions of root and rhizome traits
Functional Plant Biology, 2014Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Previously, we showed that genotypic differences in soil water extraction were associated with Drought response, but we did not study underground root and rhizome characteristics. In this study, we demonstrate a similar relationship between Drought Resistance and soil water extraction but investigate the role of underground organs. Eighteen bermudagrass genotypes (Cynodon spp.) from four climatic zones were assessed under continuous Drought at two locations with contrasting soils and climates. The criterion for Drought Resistance was the duration required to reach 50% green cover (GC50) after water was withheld. GC50, physiological traits, rhizome dry matter (RhDM), root length density (RLD) and average root diameter (ARD) were determined in both locations; water extraction was measured in one location. Large genotypic variation for Drought Resistance was observed in both locations, with GC50 being 187-277 days in a clay soil and 15-27 days in a sandy soil. Drought-resistant genotypes had greater soil water extraction and a higher water uptake rate. GC50 was correlated with relative water content (r=0.76), canopy temperature differential (r=-0.94) and photosynthetic rate (r=0.87) measured during Drought; RhDM (r=0.78 to ~0.93) before and after Drought; and ARD after Drought (r=0.82 to ~0.94); GC50 was not correlated with RLD. Ecotypes collected from the Australian Mediterranean zone had superior Drought Resistance and were characterised by a large rhizome network. This is the first comprehensive study with perennial C4 grasses describing the association between water extraction, root distribution, rhizomes and Drought Resistance.
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development and identification of a introgression line with strong Drought Resistance at seedling stage derived from oryza sativa l mating with oryza rufipogon griff
Euphytica, 2014Co-Authors: Fantao Zhang, Yi Zhou, Fenglei Cui, Xiangdong Luo, Liangxing Zhang, Xiufang Wen, Yong Wan, June Zhang, J XieAbstract:Drought stress is severely damaging during seedling stage of rice (Oryza sativa L.), which can lead to significant yield reductions. Dongxiang common wild rice (Oryza rufipogon Griff., hereafter referred to as DXWR), with strong Drought Resistance, could be a favorable genetic resource to improve the Drought Resistance of cultivated rice. Xieqingzao B (O. sativa L. ssp. indica, hereafter referred to as XB) is a representative maintainer line in hybrid rice breeding system in China. By using DXWR as donor parent, XB as recurrent parent, through continuous selfing, backcrossing and strict Drought-resistant screening, we developed a strong and stable Drought-resistant introgression line IL395 (BC5F10), whose ability of Drought Resistance was significantly increased than that of the recurrent parent XB at the seedling stage. Meanwhile, no significant differences existed among other major agronomic traits under normal condition, except for plant height. Physiological assessment revealed that IL395 exhibited a significant increase in levels of free proline and soluble sugars, which was associated with Drought Resistance. Whole genome marker analyses identified genomic segments of DXWR linking with RM171 and RM590 (chr. 10) and RM235 (chr. 12) that require further analysis as possible sources of Drought Resistance trait. These results suggest that DXWR could be a favorable genetic resource to improve the Drought Resistance of cultivated rice, and the IL395 might be a useful resource for excavating the Drought-resistant genes from DXWR.
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Drought Resistance of c4 grasses under field conditions genetic variation among a large number of bermudagrass cynodon spp ecotypes collected from different climatic zones
Journal of Agronomy and Crop Science, 2013Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Predictions of extreme weather resulting from climate change will present huge challenges for scientists trying to maintain and increase agricultural production. A greater frequency of dry periods is predicted placing emphasis on the development of plant varieties that are able to maintain performance in dry conditions. The aim of this research was to determine the genetic variation for Drought Resistance among a large range of potential pasture or turf bermudagrasses (Cynodon spp.). Four hundred and sixty genotypes including ecotypes collected from different climatic zones of Australia, and commercial cultivars were established in the field and assessed during natural and imposed Drought periods. Using descriptors of Drought Resistance such as turf quality and green cover, genotypes were classified into different groups; 436 genotypes were clustered into ten groups in one experiment, and 72 genotypes were clustered into three groups in a second. There was a high correlation of response (r = 0.78) for 47 genotypes common to both experiments suggesting that the Drought Resistance techniques used to group genotypes were robust. Physiological analyses of the genotypes within the superior Drought Resistance groups indicated that these group members were probably able to extract more available soil water during the Drought period. No commercial cultivars were found in the most Drought Resistance groups. These field studies also suggested that future collections of bermudagrass ecotypes designed to select for Drought Resistance might best be carried out from regions that experience Mediterranean climates. The field evaluations presented here did not correlate well with Drought Resistance determined in previously reported shallow lysimeter (40 cm deep) experiments.
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Drought Resistance of bermudagrass cynodon spp ecotypes collected from different climatic zones
Environmental and Experimental Botany, 2013Co-Authors: Yi Zhou, Christopher J Lambrides, S FukaiAbstract:Abstract The objectives of this paper were to (1) evaluate Drought Resistance of a large number of bermudagrass ecotypes collected from different climatic zones of regional Australia and compare their performance to commercial cultivars, (2) describe the mechanisms of Drought Resistance observed, and (3) investigate the relationship between geographic origins of the ecotypes and their Drought Resistance. Fifty-two genotypes of bermudagrass were evaluated in two field experiments using lysimeters 40 cm deep. The grasses were grown in well-watered conditions and then a Drought treatment was imposed by withholding water and excluding rainfall using a portable rain-out shelter. Two criteria were used to select for Drought Resistance, i.e. survival period (SP), defined as the number of days after water was withheld to the stage when 100% leaf firing had occurred and Days 50 defined as the days required to reach 50% green cover. These experiments suggested that genotypes with superior Drought Resistance had lower stomatal conductance in the earlier phases of the dry-down period as suggested by less water use and higher canopy temperature depression. Lower water use during the early stage of dry-down resulted in more soil available water at the end of the Drought period to extend green-leaf cover. There was no correlation between root dry matter and survival period/Days 50 . We also found some ecotypes performed better in Drought conditions than popular commercial cultivars. There was no relationship between Drought Resistance and geographic origins, suggesting that Drought resistant ecotypes could be obtained from any climatic zone sampled in this study.
Yehoshua Saranga - One of the best experts on this subject based on the ideXlab platform.
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ancestral qtl alleles from wild emmer wheat improve Drought Resistance and productivity in modern wheat cultivars
Frontiers in Plant Science, 2016Co-Authors: Lianne Merchukovnat, Tzion Fahima, Tamar Krugman, Vered Barak, Frank Ordon, Gabriel Lidzbarsky, Yehoshua SarangaAbstract:Wild emmer wheat (Triticum turgidum ssp. dicoccoides) is considered a promising source for improving stress Resistances in domesticated wheat. Here we explored the potential of selected quantitative trait loci (QTLs) from wild emmer wheat, introgressed via marker-assisted selection, to enhance Drought Resistance in elite durum (T. turgidum ssp. durum) and bread (T. aestivum) wheat cultivars. The resultant near-isogenic lines (BC3F3 and BC3F4) were genotyped using SNP array to confirm the introgressed genomic regions and evaluated in two consecutive years under well-watered (690–710 mm) and water-limited (290–320 mm) conditions. Three of the introgressed QTLs were successfully validated, two in the background of durum wheat cv. Uzan (on chromosomes 1BL and 2BS), and one in the background of bread wheat cvs. Bar Nir and Zahir (chromosome 7AS). In most cases, the QTL x environment interaction was validated in terms of improved grain yield and biomass - specifically under Drought (7AS QTL in cv. Bar Nir background), under both treatments (2BS QTL), and a greater stability across treatments (1BL QTL). The results provide a first demonstration that introgression of wild emmer QTL alleles can enhance productivity and yield stability across environments in domesticated wheat, thereby enriching the modern gene pool with essential diversity for the improvement of Drought Resistance.
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Genetic diversity for Drought Resistance in wild emmer wheat and its ecogeographical associations
Plant Cell and Environment, 2005Co-Authors: Zvi Peleg, Tzion Fahima, Shahal Abbo, Tamar Krugman, E. Nevo, Dan Yakir, Yehoshua SarangaAbstract:Wild emmer wheat ( Triticum turgidum spp. dicoccoides (Korn.) Thell.), the tetraploid progenitor of cultivated wheat, is a potential source for various agronomical traits, including Drought Resistance. The objectives of this study were to characterize (1) the genetic diversity for Drought Resistance in wild emmer wheat, and (2) the relationship between Drought responses of the wild emmer germplasm and the ecogeographical parameters of its collection sites. A total of 110 wild emmer accessions consisting of 25 populations and three control durum wheat cultivars were examined under two irrigation regimes, well-watered (’wet’) and water-limited (’dry’). Wide genetic diversity was found both between and within the wild emmer populations in most variables under each treatment. A considerable number of the wild emmer accessions exhibited an advantage in productivity (spike and total dry matter) over their cultivated counterparts. Most wild emmer wheat accessions exhibited a greater carbon isotope ratio ( d d d 13 C, indicating higher water-use efficiency) under the dry treatment and higher plasticity of d d d 13 C relative to the cultivated controls, which may have contributed to the Drought adaptations in the former. The most outstanding Drought-tolerance capacity (in term of productivity under the dry treatment and susceptibility indices) was detected in wild emmer populations originated from hot dry locations. The results suggest that wild emmer has the potential to improve Drought Resistance in cultivated wheat.
