Li Juxu, Li Man, Wang Weimin, Wang Dong, Hu Yuwei, Zhang Yunyun, Zhang Xiaoquan
College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China.
China Tobacco Zhejiang Industrial Co., Ltd, Hangzhou 310024, China.
Plant Sci. 2023 Jan;326:111528. doi: 10.1016/j.plantsci.2022.111528. Epub 2022 Nov 2.
Stigma exsertion is an essential outcrossing trait that can improve hybrid seed production efficiencies. In this study, the morphological and physiological mechanisms of cytoplasmic inheritance stigma exsertion trait expression in a tobacco line (MSK326SE) which generated from a stigma exsertion tobacco mutant through continuous backcross were investigated. Compared with its homonuclear-heteroplasmic lines (MSK326 and K326 with inserted stigmas), the exserted stigma phenotype of MSK326SE was mainly caused by corolla shortening, while was stable under different environmental temperature. The different responses of mainly endogenous hormones and expression of cell division- and expansion-related genes caused the differences in cell division and expansion in different flower organs, which further determined the lengths of the corolla. Furthermore, the significant decrease of MSK326SE corolla epidermal cell size caused corolla shortening and finally resulting in stigma exsertion. Exogenous JA could shorten the corolla and more effective increased stigma exsertion degree of MSK326SE, suggesting a potential relationship between stigma exsertion and high JA levels during early bud development. The hybrid seed production efficiency could be improved in tobacco. Our results provide a basis for elucidating the cytoplasmic inheritance stigma exsertion trait expression in tobacco while helping to improve hybrid seed production efficiency.
柱头外露是一种重要的异交性状，可提高杂交种子生产效率。本研究对一个通过连续回交从柱头外露烟草突变体培育而来的烟草品系（MSK326SE）中细胞质遗传柱头外露性状表达的形态和生理机制进行了研究。与同核异质系（柱头内陷的MSK326和K326）相比，MSK326SE的柱头外露表型主要是由花冠缩短引起的，且在不同环境温度下稳定。主要内源激素的不同响应以及细胞分裂和扩张相关基因的表达导致不同花器官中细胞分裂和扩张的差异，进而决定了花冠的长度。此外，MSK326SE花冠表皮细胞大小的显著减小导致花冠缩短，最终导致柱头外露。外源茉莉酸（JA）可缩短花冠，并更有效地提高MSK326SE的柱头外露程度，这表明在早期花蕾发育过程中柱头外露与高JA水平之间存在潜在关系。烟草的杂交种子生产效率可以得到提高。我们的结果为阐明烟草中细胞质遗传柱头外露性状表达提供了依据，同时有助于提高杂交种子生产效率。
