The Experts below are selected from a list of 57153 Experts worldwide ranked by ideXlab platform
Lin Xu - One of the best experts on this subject based on the ideXlab platform.
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transcription factors wox11 12 directly activate wox5 7 to promote root primordia initiation and Organogenesis
Plant Physiology, 2016Co-Authors: Xiaomei Hu, Lin XuAbstract:De novo Organogenesis, which gives rise to adventitious roots and shoots, is a type of plant regeneration for survival after wounding. In Arabidopsis (Arabidopsis thaliana), two main cell fate transition steps are required to establish the root primordium during de novo root Organogenesis from leaf explants. The first step from regeneration-competent cells to root founder cells involves activation of WUSCHEL-RELATED HOMEOBOX11 (WOX11) and WOX12 (WOX11/12) expression by auxin. However, the molecular mechanism controlling the second step of fate transition from root founder cells to root primordium is poorly understood. In this study, we show that the expression levels of WOX11/12 decrease while those of WOX5 and 7 (WOX5/7) increase during the transition from root founder cells to the root primordium. WOX11/12 function genetically upstream of WOX5/7, and the WOX11/12 proteins directly bind to the promoters of WOX5/7 to activate their transcription. Mutations in WOX5/7 result in defective primordium formation. Overall, our data indicate that the expression switch from WOX11/12 to WOX5/7 is critical for initiation of the root primordium during de novo root Organogenesis.
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yucca mediated auxin biogenesis is required for cell fate transition occurring during de novo root Organogenesis in arabidopsis
Journal of Experimental Botany, 2016Co-Authors: Lyuqin Chen, Hai Huang, Jianhua Tong, Langtao Xiao, Ying Ruan, Minhuan Zeng, Jiawei Wang, Lin XuAbstract:Many plant organs have the ability to regenerate a new plant after detachment or wounding via de novo Organogenesis. During de novo root Organogenesis from Arabidopsis thaliana leaf explants, endogenic auxin is essential for the fate transition of regeneration-competent cells to become root founder cells via activation of WUSCHEL-RELATED HOMEOBOX 11 (WOX11). However, the molecular events from leaf explant detachment to auxin-mediated cell fate transition are poorly understood. In this study, we used an assay to determine the concentration of indole-3-acetic acid (IAA) to provide direct evidence that auxin is produced after leaf explant detachment, a process that involves YUCCA (YUC)-mediated auxin biogenesis. Inhibition of YUC prevents expression of WOX11 and fate transition of competent cells, resulting in the blocking of rooting. Further analysis showed that YUC1 and YUC4 act quickly (within 4 hours) in response to wounding after detachment in both light and dark conditions and promote auxin biogenesis in both mesophyll and competent cells, whereas YUC5, YUC8, and YUC9 primarily respond in dark conditions. In addition, YUC2 and YUC6 contribute to rooting by providing a basal auxin level in the leaf. Overall, our study indicates that YUC genes exhibit a division of labour during de novo root Organogenesis from leaf explants in response to multiple signals.
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wox11 and 12 are involved in the first step cell fate transition during de novo root Organogenesis in arabidopsis
The Plant Cell, 2014Co-Authors: Lihong Sheng, Yingqiang Xu, Jiqin Li, Zhongnan Yang, Hai Huang, Lin XuAbstract:De novo Organogenesis is a process through which wounded or detached plant tissues or organs regenerate adventitious roots and shoots. Plant hormones play key roles in de novo Organogenesis, whereas the mechanism by which hormonal actions result in the first-step cell fate transition in the whole process is unknown. Using leaf explants of Arabidopsis thaliana, we show that the homeobox genes WUSCHEL RELATED HOMEOBOX11 (WOX11) and WOX12 are involved in de novo root Organogenesis. WOX11 directly responds to a wounding-induced auxin maximum in and surrounding the procambium and acts redundantly with its homolog WOX12 to upregulate LATERAL ORGAN BOUNDARIES DOMAIN16 (LBD16) and LBD29, resulting in the first-step cell fate transition from a leaf procambium or its nearby parenchyma cell to a root founder cell. In addition, our results suggest that de novo root Organogenesis and callus formation share a similar mechanism at initiation.
Jerome Duclercq - One of the best experts on this subject based on the ideXlab platform.
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de novo shoot Organogenesis from art to science
Trends in Plant Science, 2011Co-Authors: Jerome Duclercq, B S Sangwannorreel, Manuella Catterou, Rajbir S SangwanAbstract:In vitro shoot Organogenesis and plant regeneration are crucial for both plant biotechnology and the fundamental study of plant biology. Although the importance of auxin and cytokinin has been known for more than six decades, the underlying molecular mechanisms of their function have only been revealed recently. Advances in identifying new Arabidopsis genes, implementing live-imaging tools and understanding cellular and molecular networks regulating de novo shoot Organogenesis have helped to redefine the empirical models of shoot Organogenesis and plant regeneration. Here, we review the functions and interactions of genes that control key steps in two distinct developmental processes: de novo shoot Organogenesis and lateral root formation.
Rajbir S Sangwan - One of the best experts on this subject based on the ideXlab platform.
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de novo shoot Organogenesis from art to science
Trends in Plant Science, 2011Co-Authors: Jerome Duclercq, B S Sangwannorreel, Manuella Catterou, Rajbir S SangwanAbstract:In vitro shoot Organogenesis and plant regeneration are crucial for both plant biotechnology and the fundamental study of plant biology. Although the importance of auxin and cytokinin has been known for more than six decades, the underlying molecular mechanisms of their function have only been revealed recently. Advances in identifying new Arabidopsis genes, implementing live-imaging tools and understanding cellular and molecular networks regulating de novo shoot Organogenesis have helped to redefine the empirical models of shoot Organogenesis and plant regeneration. Here, we review the functions and interactions of genes that control key steps in two distinct developmental processes: de novo shoot Organogenesis and lateral root formation.
Anil Kumar - One of the best experts on this subject based on the ideXlab platform.
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Shoot Organogenesis and assessment of clonal fidelity of regenerated plants of Ocimum tenuiflorum L.: Queen of Herbs
Vegetos, 2020Co-Authors: Diwakar Aggarwal, Nisha Neeti, M. Sudhakar Reddy, Anil KumarAbstract:An efficient and reliable shoot Organogenesis protocol was developed from leaf explants taken from microshoots of Ocimum tenuiflorum L . Cultures were established using nodal explants taken from field grown mature plant on MS medium supplemented with 6-benzyladenine (BA; 2.5 μM). The effect of different cytokinins namely BA, kinetin (KIN) and thidiazuron (TDZ) in combination with 0.5 μM α-naphthalene acetic acid (NAA) was examined on shoot proliferation and elongation. Maximum number of shoots per culture vessel (38) was recorded on MS medium supplemented with 5.0 μM BA, whereas the maximum number of elongated shoots per culture vessel (15) along with maximum shoot length (4.80 cm) was observed on medium supplemented with 2.5 μM BA. Shoot Organogenesis was attempted from the segments of fully expanded leafs and 34.45% explants regenerated shoots on MS medium supplemented with 5.0 µM each of BA and NAA. Incorporation of cefotaxime (300 mg/l) was found to be beneficial for shoot Organogenesis and further increased shoot regeneration frequency to 36% explants. On the other hand, addition of carbenicillin into the medium was found to inhibit shoot Organogenesis . For root induction in microshoots, among various auxins used, IBA was found to be the best. A pulse treatment of 50.0 μM IBA for 36 h improved rooting of microshoots and a maximum of 89% microshoots rooted. Rooted microshoots were successfully acclimatized under polyhouse conditions with a survival rate of 80%. Later acclimatized plants were established in their natural conditions. Random Amplified polymorphic DNA and Inter Simple Sequence Repeat markers established a clonal fidelity of micropropagated plants with that of mother plant.
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Direct shoot Organogenesis from leaf explants of Populus deltoides and changes in selected enzymatic activities
Physiology and Molecular Biology of Plants, 2020Co-Authors: Saloni Sharma, M. S. Reddy, Anil KumarAbstract:The direct shoot Organogenesis was achieved from leaf explant of two commercially important clones of Populus deltoides on MS medium enriched with 15 mg/l adenine sulphate, 5 mg/l Ascorbic acid, 250 mg/l (NH_4)_2SO_4 (referred to as PD1 medium) supplemented with 2.5 µM each of 6-benzylaminopurine and indole-3-acetic acid. Higher shoot organogenic potential was recorded from the explants of clone ‘G48’ as compared to clone ‘L34’. The age of leaf explant also affected the shoot organogenic potential, and maximum shoot Organogenesis was recorded in case of 5th leaf from the top of microshoot. Histological studies revealed altered cell division resulting in the formation of meristematic pockets after 5 days of culture, these meristematic pockets grew into dome protuberances by 10th day. Organized shoots were visible after 15 days of culture. A clear three phases of shoot Organogenesis viz induction (0–4 days), initiation and organization (4–10 days) and growth (11–16 days onwards) were observed. Marked variation in the activity of enzymes such as catalase, peroxidase, polyphenol oxidase and acid phosphatase was observed during these phases. The activity of these enzymes was found to increase in cultures grown on the medium resulting in shoot Organogenesis during shoot development (after 7 days of culture).
Manish N. Raizada - One of the best experts on this subject based on the ideXlab platform.
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Ethylene and shoot regeneration: hookless1 modulates de novo shoot Organogenesis in Arabidopsis thaliana
Plant Cell Reports, 2008Co-Authors: Steven P. Chatfield, Manish N. RaizadaAbstract:We have investigated the role of ethylene in shoot regeneration from cotyledon explants of Arabidopsis thaliana . We examined the ethylene sensitivity of five ecotypes representing both poor and prolific shoot regenerators and identified Dijon-G, a poor regenerator, as an ecotype with dramatically enhanced ethylene sensitivity. However, inhibiting ethylene action with silver nitrate generally reduced shoot Organogenesis in ecotypes capable of regeneration. In ecotype Col-0, we found that ethylene-insensitive mutants ( etr1-1, ein2-1, ein4, ein7 ) exhibited reduced shoot regeneration rates, whereas constitutive ethylene response mutants ( ctr1-1, ctr1-12 ) increased the proportion of explants producing shoots. Our experiments with ethylene over-production mutants ( eto1 , eto2 and eto3 ) indicate that the ethylene biosynthesis inhibitor gene, ETO1 , can act as an inhibitor of shoot regeneration. Pharmacological elevation of ethylene levels was also found to significantly increase the proportion of explants regenerating shoots. We determined that the hookless1 ( hls1-1 ) mutant, a suppressor of the ethylene response phenotypes of ctr1 and eto1 mutants, is capable of dramatically enhancing shoot Organogenesis. The effects of ACC and loss of HLS1 function on shoot Organogenesis were found to be largely additive.
