EMS derived wheat mutant BIG8-1 (Triticum aestivum L.)— a new drought tolerant mutant wheat line

Drought response in wheat is considered a highly complex process, since it is a multigenic trait; nevertheless, breeding programs are continuously searching for new wheat varieties with characteristics for drought tolerance. In a previous study, we demonstrated the effectiveness of a mutant known as RYNO3936 that could survive 14 days without water. In this study, we reveal another mutant known as BIG8-1 that can endure severe water deficit stress (21 days without water) with superior drought response characteristics. Phenotypically, the mutant plants had broader leaves, including a densely packed fibrous root architecture that was not visible in the WT parent plants. During mild (day 7) drought stress, the mutant could maintain its relative water content, chlorophyll content, maximum quantum yield of PSII (Fv/Fm) and stomatal conductance, with no phenotypic symptoms such as wilting or senescence despite a decrease in soil moisture content. It was only during moderate (day 14) and severe (day 21) water deficit stress that a decline in those variables was evident. Furthermore, the mutant plants also displayed a unique preservation of metabolic activity, which was confirmed by assessing the accumulation of free amino acids and increase of antioxidative enzymes (peroxidases and glutathione S-transferase). Proteome reshuffling was also observed, allowing slow degradation of essential proteins such as RuBisCO during water deficit stress. The LC-MS/MS data revealed a high abundance of proteins involved in energy and photosynthesis under well-watered conditions, particularly Serpin-Z2A and Z2B, SGT1 and Calnexin-like protein. However, after 21 days of water stress, the mutants expressed ABC transporter permeases and xylanase inhibitor protein, which are involved in the transport of amino acids and protecting cells, respectively. This study characterizes a new mutant BIG8-1 with drought-tolerant characteristics suited for breeding programs.The National Research Foundation of South Africa (NRF Competitive Programme for Rated Researchers (CPRR); NRF Incentive Funding for Rated Researchers Programme (IFR) and the Winter Cereal Trust.https://www.mdpi.com/journal/ijmsam2021Forestry and Agricultural Biotechnology Institute (FABI)Plant Production and Soil Scienc

Wheat line “RYNO3936” is associated with delayed water stress-induced leaf senescence and rapid water-deficit stress recovery

Random mutagenesis was applied to produce a new wheat mutant (RYNO3926) with superior characteristics regarding tolerance to water deficit stress induced at late booting stage. The mutant also displays rapid recovery from water stress conditions. Under water stress conditions mutant plants reached maturity faster and produced more seeds than its wild type wheat progenitor. Wild-type Tugela DN plants died within 7 days after induction of water stress induced at late booting stage, while mutant plants survived by maintaining a higher relative moisture content (RMC), increased total chlorophyll, and a higher photosynthesis rate and stomatal conductance. Analysis of the proteome of mutant plants revealed that they better regulate post-translational modification (SUMOylation) and have increased expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) proteins. Mutant plants also expressed unique proteins associated with dehydration tolerance including abscisic stress-ripening protein, cold induced protein, cold-responsive protein, dehydrin, Group 3 late embryogenesis, and a lipoprotein (LAlv9) belonging to the family of lipocalins. Overall, our results suggest that our new mutant RYNO3936 has a potential for inclusion in future breeding programs to improve drought tolerance under dryland conditions.Table S2 : Blast2GO results from the peptides obtained after LC-ESI-MS/MS analysis of total protein isolated from RYNO3936 before (day 0), and after induction of water stress (days 7 and 14), and after recovery and regrowth (day 21).Table S3 : List of proteins expressed in RYNO3936 before (day 0), and after induction of water stress (days 7 and 14), as well as after recovery and regrowth (day 21). Indicated are the sequence name, protein identity, length and number of hits, number of GO terms, and e-value. The cluster numbers correspond to that given in Figure S2.Figure S1 : Proportional contribution of proteins expressed in RYNO3936 to the different functional categories, where (A) biological processes; (B) cellular component; and (C) molecular function.Figure S2 : Cluster image generated by Java TreeView (Saldanha, 2004) of the proteins obtained after LC-ESI-MS/MS analysis of total protein isolated from RYNO3936 before (day 0), and after induction of water stress (days 7 and 14), and after recovery and regrowth (day 21). Red bands show up-regulated proteins, whereas green bands show down-regulated proteins.The National Research Foundation of South Africa (NRF Competitive Programme for Rated Researchers (CPRR), NRF Incentive Funding for Rated Researchers Programme (IFR) and the Winter Cereal Trust.http://www.frontiersin.org/Plant_Scienceam2020Forestry and Agricultural Biotechnology Institute (FABI)Plant Production and Soil Scienc

Wheat line “RYNO3936” is associated with delayed water stress-induced leaf senescence and rapid water-deficit stress recovery

CITATION: Le Roux, M. S. L., et al. 2020. Wheat line “RYNO3936” is associated with delayed water stress-induced leaf senescence and rapid water-deficit stress recovery. Frontiers in Plant Science, 11:1053, doi:10.3389/fpls.2020.01053.The original publication is available at https://www.frontiersin.orgPublication of this article was funded by the Stellenbosch University Open Access FundRandom mutagenesis was applied to produce a new wheat mutant (RYNO3926) with superior characteristics regarding tolerance to water deficit stress induced at late booting stage. The mutant also displays rapid recovery from water stress conditions. Under water stress conditions mutant plants reached maturity faster and produced more seeds than its wild type wheat progenitor. Wild-type Tugela DN plants died within 7 days after induction of water stress induced at late booting stage, while mutant plants survived by maintaining a higher relative moisture content (RMC), increased total chlorophyll, and a higher photosynthesis rate and stomatal conductance. Analysis of the proteome of mutant plants revealed that they better regulate post-translational modification (SUMOylation) and have increased expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) proteins. Mutant plants also expressed unique proteins associated with dehydration tolerance including abscisic stress-ripening protein, cold induced protein, cold-responsive protein, dehydrin, Group 3 late embryogenesis, and a lipoprotein (LAlv9) belonging to the family of lipocalins. Overall, our results suggest that our new mutant RYNO3936 has a potential for inclusion in future breeding programs to improve drought tolerance under dryland conditions.https://www.frontiersin.org/articles/10.3389/fpls.2020.01053/fullPublisher's versio