Induced Mutations for Plant Breeding·Agricultural Biotechnology
KE Yuzhou, WANG Pingsong, DUAN Lili, MO Zejun, HE Yi, YU Qiwei, XIONG Jing, LIU Renxiang
At present, the planting area of tobacco hybrid and sterile line is more and more extensive in China, male sterile line is a favorable material for tobacco hybrid. However, the molecular mechanism of male sterility in tobacco is unclear. To investigate the molecular mechanism of cytoplasmic male sterility in tobacco,tobacco sterile lines and their maintainers were used in this study, paraffin sectioning and mitochondrial proteomics combined with bioinformatics analysis were conducted during flower bud differentiation. The results show that the abortive process of tobacco male sterile line occurs at the stage of stamen primordia germination and differentiation;A total of 113 differentially expressed mitochondrial proteins were screened out by proteomic analysis. During respiratory metabolism, the expression of key regulatory proteases such as pyrophosphatase, isocitrate dehydrogenase, malate dehydrogenase and phosphate hexose isomerase was down-regulated, and the expression of δ and α subunits of ATP synthase was abnormal;During the synthesis, modification, and transportation of mitochondrial proteins, abnormal expression of L4e and L7 in large subunit and SAe in small subunit of ribosomal RNA, and enzymes such as enolase, endoplasmic reticulum protein processing enzyme, protein disulfide isomerase and other functional protein structural modification enzymes were down-regulated.It is inferred from the above results that cytoplasmic male sterility of tobacco is caused by mitochondrial dysfunction due to the blocked synthesis, modification and import of mitochondrial proteins.Specifically, protease expression in mitochondrial respiratory metabolic pathway is down-regulated and ATP synthesis is blocked, which cannot provide sufficient energy for the rapid division and differentiation of microspores during pollen formation, and inhibited the formation and development of microspore, then displayzed as male sterility. The results of this study lay an important foundation for further research on male sterility mechanism.