The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
M Djanaguiraman - One of the best experts on this subject based on the ideXlab platform.
-
quantifying pearl millet response to high temperature stress thresholds sensitive stages genetic variability and relative sensitivity of pollen and Pistil
Plant Cell and Environment, 2018Co-Authors: M Djanaguiraman, Ramasamy Perumal, Ignacio A Ciampitti, S K Gupta, P V V PrasadAbstract:The objectives were to (1) quantify high temperature (HT) stress impacts at different growth stages (season long, booting to seed-set and booting to maturity) on various yield components; (2) identify the most sensitive stage(s) to short episodes of HT stress during reproductive development; (3) understand the genetic variations for HT stress tolerance based on cardinal temperatures for pollen germination; and (4) determine relative sensitivity of pollen and Pistil to HT stress and associated tolerance or susceptible mechanisms in pearl millet. High temperature stress (≥36/26°C) imposed at different stages and durations caused decrease in number of seeds, individual seed weight and seed yield. Two periods (10–12 days and 2–0 days before anthesis) were identified as most sensitive to short episodes of stress, causing maximum decreases in pollen germination percentage and seeds numbers. HT stresses of ≥36/26°C results in floret sterility. Pistils were relatively more sensitive than pollen grains, causing decreased number of seeds and seed yield. HT stress increased the reactive oxygen species contents and decreased the activity of the antioxidant enzymes in both pollen and Pistils. Under HT stress, Pistils had relatively higher reactive oxygen species and lower antioxidant enzymes activity compared with pollen grains, which explains greater susceptibility of Pistils.
-
sensitivity of sorghum pollen and Pistil to high temperature stress
Plant Cell and Environment, 2018Co-Authors: M Djanaguiraman, Ramasamy Perumal, Ignacio A Ciampitti, S V K Jagadish, Ruth Welti, P V V PrasadAbstract:High temperature (HT) decreases seed-set percentage in sorghum [Sorghum bicolor (L.) Moench]. The relative sensitivity of pollen and particularly Pistil and the mechanistic response that induces tolerance or susceptibility to HT is not well known and hence is the major objective of this research. The male sterile (ATx399) and fertile (RTx430) lines were exposed to 30/20 °C (optimum temperature; OT), 36/26 °C (HT1) and 39/29 °C (HT2) from the start of booting to seed-set in a controlled environment. Similarly, in the field, HT stress was imposed using heat tents. HT stress decreased pollen germination. Relatively high levels of reactive oxygen species, and decreased antioxidant enzyme activity and phospholipid unsaturation were observed in pollen compared to Pistil under HT. The severe cell organelle damage was observed in pollen and Pistil at 36/26 and 39/29 °C, respectively. The seed-set percentage was higher in HT stressed Pistil pollinated with OT pollen. Direct and reciprocal crosses indicate that pollen was relatively more sensitive with larger decreases in seed-set percentage than Pistil under HT stress. The negative impact was greater in pollen than Pistil at relatively lower temperatures. Overall, pollen was relatively more sensitive than Pistil to HT stress because it is more susceptible to oxidative damage than Pistil.
Ravishankar Palanivelu - One of the best experts on this subject based on the ideXlab platform.
-
pathfinding in angiosperm reproduction pollen tube guidance by Pistils ensures successful double fertilization
Wiley Interdisciplinary Reviews-Developmental Biology, 2012Co-Authors: Ravishankar Palanivelu, Tatsuya TsukamotoAbstract:Sexual reproduction in flowering plants is unique in multiple ways. Distinct multicellular gametophytes contain either a pair of immotile, haploid male gametes (sperm cells) or a pair of female gametes (haploid egg cell and homodiploid central cell). After pollination, the pollen tube, a cellular extension of the male gametophyte, transports both male gametes at its growing tip and delivers them to the female gametes to affect double fertilization. The pollen tube travels a long path and sustains its growth over a considerable amount of time in the female reproductive organ (Pistil) before it reaches the ovule, which houses the female gametophyte. The Pistil facilitates the pollen tube's journey by providing multiple, stage-specific, nutritional, and guidance cues along its path. The pollen tube interacts with seven different Pistil cell types prior to completing its journey. Consequently, the pollen tube has a dynamic gene expression program allowing it to continuously reset and be receptive to multiple Pistil signals as it migrates through the Pistil. Here, we review the studies, including several significant recent advances, that led to a better understanding of the multitude of cues generated by the Pistil tissues to assist the pollen tube in delivering the sperm cells to the female gametophyte. We also highlight the outstanding questions, draw attention to opportunities created by recent advances and point to approaches that could be undertaken to unravel the molecular mechanisms underlying pollen tube-Pistil interactions.
-
pathfinding in angiosperm reproduction pollen tube guidance by Pistils ensures successful double fertilization
Wiley Interdisciplinary Reviews-Developmental Biology, 2012Co-Authors: Ravishankar Palanivelu, Tatsuya TsukamotoAbstract:Sexual reproduction in flowering plants is unique in multiple ways. Distinct multicellulargametophytescontaineitherapairofimmotile,haploidmalegametes (sperm cells) or a pair of female gametes (haploid egg cell and homodiploid central cell). After pollination, the pollen tube, a cellular extension of the male gametophyte, transports both male gametes at its growing tip and delivers them to the female gametes to affect double fertilization. The pollen tube travels a long path and sustains its growth over a considerable amount of time in the female reproductive organ (Pistil) before it reaches the ovule, which houses the female gametophyte. The Pistil facilitates the pollen tube’s journey by providing multiple, stage-specific, nutritional, and guidance cues along its path. The pollen tube interacts with seven different Pistil cell types prior to completing its journey. Consequently, the pollen tube has a dynamic gene expression program allowing it to continuously reset and be receptive to multiple Pistil signals as it migrates through the Pistil. Here, we review the studies, including several significant recent advances, that led to a better understanding of the multitude of cues generated by the Pistil tissues to assist the pollen tube in delivering the sperm cells to the female gametophyte. We also highlight the outstanding questions, draw attention to opportunities created by recent advances and point to approaches that could be undertaken to unravel the molecular mechanisms underlying pollen tube‐Pistil
-
Functional genomics of pollen tube-Pistil interactions in Arabidopsis.
Biochemical Society Transactions, 2010Co-Authors: Ravishankar Palanivelu, Mark A JohnsonAbstract:The pollen tube represents an attractive model system for functional genomic analysis of the cell–cell interactions that mediate guided cellular growth. The pollen tube extends through Pistil tissues and responds to guidance cues that direct the tube towards an ovule, where it releases sperm for fertilization. Pollen is readily isolated from anthers, where it is produced, and can be induced to produce a tube in vitro. Interestingly, pollen tube growth is significantly enhanced in Pistils, and pollen tubes are rendered competent to respond to guidance cues after growth in a Pistil. This potentiation of the pollen tube by the Pistil suggested that pollen tubes alter their gene-expression programme in response to their environment. Recently, the transcriptomes of pollen tubes grown in vitro or through Pistil tissues were determined. Significant changes in the transcriptome were found to accompany growth in vitro and through the Pistil tissues. Reverse genetic analysis of pollen-tube-induced genes identified a new set of factors critical for pollen tube extension and navigation of the Pistil environment. Recent advances reviewed in the present paper suggest that functional genomic analysis of pollen tubes has the potential to uncover the regulatory networks that shape the genetic architecture of the pollen tube as it responds to migratory cues produced by the Pistil.
-
penetration of the stigma and style elicits a novel transcriptome in pollen tubes pointing to genes critical for growth in a Pistil
PLOS Genetics, 2009Co-Authors: Alexander R Leydon, Mark A Johnson, Ann Manziello, Ritu Pandey, David B Mount, S Z Denic, Bane Vasic, Ravishankar PalaniveluAbstract:Pollen tubes extend through Pistil tissues and are guided to ovules where they release sperm for fertilization. Although pollen tubes can germinate and elongate in a synthetic medium, their trajectory is random and their growth rates are slower compared to growth in Pistil tissues. Furthermore, interaction with the Pistil renders pollen tubes competent to respond to guidance cues secreted by specialized cells within the ovule. The molecular basis for this potentiation of the pollen tube by the Pistil remains uncharacterized. Using microarray analysis in Arabidopsis, we show that pollen tubes that have grown through stigma and style tissues of a Pistil have a distinct gene expression profile and express a substantially larger fraction of the Arabidopsis genome than pollen grains or pollen tubes grown in vitro. Genes involved in signal transduction, transcription, and pollen tube growth are overrepresented in the subset of the Arabidopsis genome that is enriched in Pistil-interacted pollen tubes, suggesting the possibility of a regulatory network that orchestrates gene expression as pollen tubes migrate through the Pistil. Reverse genetic analysis of genes induced during pollen tube growth identified seven that had not previously been implicated in pollen tube growth. Two genes are required for pollen tube navigation through the Pistil, and five genes are required for optimal pollen tube elongation in vitro. Our studies form the foundation for functional genomic analysis of the interactions between the pollen tube and the Pistil, which is an excellent system for elucidation of novel modes of cell–cell interaction.
P V V Prasad - One of the best experts on this subject based on the ideXlab platform.
-
quantifying pearl millet response to high temperature stress thresholds sensitive stages genetic variability and relative sensitivity of pollen and Pistil
Plant Cell and Environment, 2018Co-Authors: M Djanaguiraman, Ramasamy Perumal, Ignacio A Ciampitti, S K Gupta, P V V PrasadAbstract:The objectives were to (1) quantify high temperature (HT) stress impacts at different growth stages (season long, booting to seed-set and booting to maturity) on various yield components; (2) identify the most sensitive stage(s) to short episodes of HT stress during reproductive development; (3) understand the genetic variations for HT stress tolerance based on cardinal temperatures for pollen germination; and (4) determine relative sensitivity of pollen and Pistil to HT stress and associated tolerance or susceptible mechanisms in pearl millet. High temperature stress (≥36/26°C) imposed at different stages and durations caused decrease in number of seeds, individual seed weight and seed yield. Two periods (10–12 days and 2–0 days before anthesis) were identified as most sensitive to short episodes of stress, causing maximum decreases in pollen germination percentage and seeds numbers. HT stresses of ≥36/26°C results in floret sterility. Pistils were relatively more sensitive than pollen grains, causing decreased number of seeds and seed yield. HT stress increased the reactive oxygen species contents and decreased the activity of the antioxidant enzymes in both pollen and Pistils. Under HT stress, Pistils had relatively higher reactive oxygen species and lower antioxidant enzymes activity compared with pollen grains, which explains greater susceptibility of Pistils.
-
sensitivity of sorghum pollen and Pistil to high temperature stress
Plant Cell and Environment, 2018Co-Authors: M Djanaguiraman, Ramasamy Perumal, Ignacio A Ciampitti, S V K Jagadish, Ruth Welti, P V V PrasadAbstract:High temperature (HT) decreases seed-set percentage in sorghum [Sorghum bicolor (L.) Moench]. The relative sensitivity of pollen and particularly Pistil and the mechanistic response that induces tolerance or susceptibility to HT is not well known and hence is the major objective of this research. The male sterile (ATx399) and fertile (RTx430) lines were exposed to 30/20 °C (optimum temperature; OT), 36/26 °C (HT1) and 39/29 °C (HT2) from the start of booting to seed-set in a controlled environment. Similarly, in the field, HT stress was imposed using heat tents. HT stress decreased pollen germination. Relatively high levels of reactive oxygen species, and decreased antioxidant enzyme activity and phospholipid unsaturation were observed in pollen compared to Pistil under HT. The severe cell organelle damage was observed in pollen and Pistil at 36/26 and 39/29 °C, respectively. The seed-set percentage was higher in HT stressed Pistil pollinated with OT pollen. Direct and reciprocal crosses indicate that pollen was relatively more sensitive with larger decreases in seed-set percentage than Pistil under HT stress. The negative impact was greater in pollen than Pistil at relatively lower temperatures. Overall, pollen was relatively more sensitive than Pistil to HT stress because it is more susceptible to oxidative damage than Pistil.
Koji Murai - One of the best experts on this subject based on the ideXlab platform.
-
class d and bsister mads box genes are associated with ectopic ovule formation in the Pistil like stamens of alloplasmic wheat triticum aestivum l
Plant Molecular Biology, 2009Co-Authors: Kaori Yamada, Tatsunori Saraike, Naoki Shitsukawa, Chizuru Hirabayashi, Shigeo Takumi, Koji MuraiAbstract:Homeotic transformation of stamens into Pistil-like structures (Pistillody) has been reported in cytoplasmic substitution (alloplasmic) lines of bread wheat (Triticum aestivum L.) that have the cytoplasm of a related wild species, Aegilops crassa. An ectopic ovule differentiates in the Pistil-like stamen in the alloplasmic wheat. The SEEDSTICK (STK)—like class D MADS-box gene, wheat STK (WSTK), was expressed in the primordia of ectopic ovules in the Pistil-like stamens as well as in the true Pistil, suggesting that ectopic ovule formation results from WSTK expression in the Pistil-like stamens of alloplasmic wheat. The ectopic ovule is abnormal as it fails to form complete integuments. Based on the expression pattern of WSTK and Bsister MADS-box gene, WBsis (wheat Bsister), we conclude that WSTK plays a role in determination of ovule identity in the Pistil-like stamen, but complete ovule development fails due to aberrant expression of WBsis.
-
Altered expression of wheat AINTEGUMENTA homolog, WANT-1, in Pistil and Pistil-like transformed stamen of an alloplasmic line with Aegilops crassa cytoplasm
Development Genes and Evolution, 2009Co-Authors: Kota Mizumoto, Chizuru Hirabayashi, Koji Murai, Hitoshi Hatano, Shigeo TakumiAbstract:Homeotic transformation of stamens into Pistil-like structures, called Pistillody, has been reported in some alloplasmic common wheat lines with Aegilops crassa cytoplasm. An alloplasmic line of Chinese Spring ditelosomic 7BS (CSdt7BS) with Ae. crassa cytoplasm lacking the long arm of the chromosome 7B shows Pistillody, and the Pistils and transformed stamens are sterile due to abnormal ovule development. To elucidate the molecular mechanism of the ovule abnormality, we compared the expression profiles of floral organs between euplasmic and alloplasmic CSdt7BS lines. Two differential display methods of mRNA profiling demonstrated that Ae. crassa cytoplasm largely affects nuclear gene expression profiles of common wheat. Of the differentially expressed genes, a wheat AINTEGUMENTA ( ANT ) homolog, WANT-1 , was preferentially expressed in Pistils but not in stamens, and accumulation of the transcript was limited to ovule primordia at the floral organ development stage. In alloplasmic wheat, WANT-1 expression was patchy and weak at the ovule-development stages. On the other hand, no significant difference in gene expression patterns of wheat AGAMOUS ( AG ) homologs ( WAG-1 and WAG-2 ) was observed between fertile and sterile Pistils. These results indicated that alteration of gene expression after initiation of ovule primordia results in abnormal ovule development, and that the aberrant ovule formation is at least partly associated with the weak expression of WANT-1 around ovule primordia in alloplasmic wheat with Ae. crassa cytoplasm.
-
wag a wheat agamous homolog is associated with development of Pistil like stamens in alloplasmic wheats
Sexual Plant Reproduction, 2003Co-Authors: Akira Meguro, Shigeo Takumi, Yasunari Ogihara, Koji MuraiAbstract:Pistillody, homeotic transformation of stamens into Pistil-like structures, has been reported in cytoplasmic substitution (alloplasmic) lines of common wheat (Triticum aestivum) with Aegilops crassa cytoplasm. The induction of Pistillody is suppressed by the Rfd1 gene detected on the long arm of chromosome 7B in wheat cultivar 'Chinese Spring' (CS). Because of the absence of Rfd1, the alloplasmic line CS ditelosomic 7BS [(cr)-CSdt7BS] lacking the long arm of chromosome 7B exhibits Pistillody in all florets, whereas the euplasmic CS ditelosomic 7BS (CSdt7BS) with normal cytoplasm forms normal stamens. To study the molecular mechanism of Pistillody caused by nuclear-cytoplasm interaction in alloplasmic wheat, we cloned and characterized a wheat AGAMOUS homolog, WAG. The WAG gene copy number in the wheat genome was estimated at three, located on the homoeologous group 1 chromosomes. Northern blot analysis with a normal wheat line revealed that the transcription level of WAG was lower in young spikes and increased during spike development. The highest expression was observed in spikes at the booting to heading stage. The 1.1 kb WAG transcript accumulated in both the reproductive (Pistil and stamen) and non-reproductive (palea and lemma) portions of spikes at the heading stage, whereas an extra transcript of different molecular size (1.3 kb) was observed in Pistil-like stamens of line (cr)-CSdt7BS as well as in Pistils of CSdt7BS and (cr)-CSdt7BS. These results suggest that the product of the 1.3 kb WAG transcript is involved in Pistil development and is associated with Pistillody caused by a nuclear-cytoplasm interaction in alloplasmic wheat.
Shigeo Takumi - One of the best experts on this subject based on the ideXlab platform.
-
class d and bsister mads box genes are associated with ectopic ovule formation in the Pistil like stamens of alloplasmic wheat triticum aestivum l
Plant Molecular Biology, 2009Co-Authors: Kaori Yamada, Tatsunori Saraike, Naoki Shitsukawa, Chizuru Hirabayashi, Shigeo Takumi, Koji MuraiAbstract:Homeotic transformation of stamens into Pistil-like structures (Pistillody) has been reported in cytoplasmic substitution (alloplasmic) lines of bread wheat (Triticum aestivum L.) that have the cytoplasm of a related wild species, Aegilops crassa. An ectopic ovule differentiates in the Pistil-like stamen in the alloplasmic wheat. The SEEDSTICK (STK)—like class D MADS-box gene, wheat STK (WSTK), was expressed in the primordia of ectopic ovules in the Pistil-like stamens as well as in the true Pistil, suggesting that ectopic ovule formation results from WSTK expression in the Pistil-like stamens of alloplasmic wheat. The ectopic ovule is abnormal as it fails to form complete integuments. Based on the expression pattern of WSTK and Bsister MADS-box gene, WBsis (wheat Bsister), we conclude that WSTK plays a role in determination of ovule identity in the Pistil-like stamen, but complete ovule development fails due to aberrant expression of WBsis.
-
Altered expression of wheat AINTEGUMENTA homolog, WANT-1, in Pistil and Pistil-like transformed stamen of an alloplasmic line with Aegilops crassa cytoplasm
Development Genes and Evolution, 2009Co-Authors: Kota Mizumoto, Chizuru Hirabayashi, Koji Murai, Hitoshi Hatano, Shigeo TakumiAbstract:Homeotic transformation of stamens into Pistil-like structures, called Pistillody, has been reported in some alloplasmic common wheat lines with Aegilops crassa cytoplasm. An alloplasmic line of Chinese Spring ditelosomic 7BS (CSdt7BS) with Ae. crassa cytoplasm lacking the long arm of the chromosome 7B shows Pistillody, and the Pistils and transformed stamens are sterile due to abnormal ovule development. To elucidate the molecular mechanism of the ovule abnormality, we compared the expression profiles of floral organs between euplasmic and alloplasmic CSdt7BS lines. Two differential display methods of mRNA profiling demonstrated that Ae. crassa cytoplasm largely affects nuclear gene expression profiles of common wheat. Of the differentially expressed genes, a wheat AINTEGUMENTA ( ANT ) homolog, WANT-1 , was preferentially expressed in Pistils but not in stamens, and accumulation of the transcript was limited to ovule primordia at the floral organ development stage. In alloplasmic wheat, WANT-1 expression was patchy and weak at the ovule-development stages. On the other hand, no significant difference in gene expression patterns of wheat AGAMOUS ( AG ) homologs ( WAG-1 and WAG-2 ) was observed between fertile and sterile Pistils. These results indicated that alteration of gene expression after initiation of ovule primordia results in abnormal ovule development, and that the aberrant ovule formation is at least partly associated with the weak expression of WANT-1 around ovule primordia in alloplasmic wheat with Ae. crassa cytoplasm.
-
wag a wheat agamous homolog is associated with development of Pistil like stamens in alloplasmic wheats
Sexual Plant Reproduction, 2003Co-Authors: Akira Meguro, Shigeo Takumi, Yasunari Ogihara, Koji MuraiAbstract:Pistillody, homeotic transformation of stamens into Pistil-like structures, has been reported in cytoplasmic substitution (alloplasmic) lines of common wheat (Triticum aestivum) with Aegilops crassa cytoplasm. The induction of Pistillody is suppressed by the Rfd1 gene detected on the long arm of chromosome 7B in wheat cultivar 'Chinese Spring' (CS). Because of the absence of Rfd1, the alloplasmic line CS ditelosomic 7BS [(cr)-CSdt7BS] lacking the long arm of chromosome 7B exhibits Pistillody in all florets, whereas the euplasmic CS ditelosomic 7BS (CSdt7BS) with normal cytoplasm forms normal stamens. To study the molecular mechanism of Pistillody caused by nuclear-cytoplasm interaction in alloplasmic wheat, we cloned and characterized a wheat AGAMOUS homolog, WAG. The WAG gene copy number in the wheat genome was estimated at three, located on the homoeologous group 1 chromosomes. Northern blot analysis with a normal wheat line revealed that the transcription level of WAG was lower in young spikes and increased during spike development. The highest expression was observed in spikes at the booting to heading stage. The 1.1 kb WAG transcript accumulated in both the reproductive (Pistil and stamen) and non-reproductive (palea and lemma) portions of spikes at the heading stage, whereas an extra transcript of different molecular size (1.3 kb) was observed in Pistil-like stamens of line (cr)-CSdt7BS as well as in Pistils of CSdt7BS and (cr)-CSdt7BS. These results suggest that the product of the 1.3 kb WAG transcript is involved in Pistil development and is associated with Pistillody caused by a nuclear-cytoplasm interaction in alloplasmic wheat.
