Liu Guangyang, Liu Fengjun, Jiang Huiyan, Li Jun, Jing Jing, Jin Qijiang, Wang Yanjie, Qian Ping, Xu Yingchun
Key Laboratory of Landscape Agriculture, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
Suzhou Academy of Agricultural Sciences, Suzhou 215000, China.
Plants (Basel). 2023 Jan 13;12(2):387. doi: 10.3390/plants12020387.
Self-fertilization rate is an essential index of lotus reproductive system development, and pollen activity is a key factor affecting lotus seed setting rate. Based on cytology and molecular biology, this study addresses the main reasons for the low self-set rate of double lotus. It takes two different double lotus breeds into consideration, namely 'Sijingganshan' with a low self-crossing rate and 'Jinfurong' with a high self-crossing rate. Cytological analysis results showed that the pollen abortion caused by excessive degradation of tapetum during the single phase was the root cause for the low self-mating rate of double lotus. Subsequent transcriptome analysis revealed that the gene related to programmed tapetum cell death was significantly differentially expressed during the critical period of abortion, which further verified the specific expression of in anthers. It was found that the expression level of in 'Sijingganshan' at the mononuclear stage of its microspore development was significantly higher than that of 'Jinfurong' at the same stage. The overexpression of resulted in the premature degradation of the tapetum and significantly decreased seed setting rate. These results indicated that the gene regulated the pollen abortion of double lotus. The mechanism causing a low seed setting rate for double lotus was preliminarily revealed, which provided a theoretical basis for cultivating lotus varieties with both flower and seed.
自交结实率是荷花生殖系统发育的重要指标，花粉活力是影响荷花结实率的关键因素。本研究基于细胞学和分子生物学，探讨了重瓣荷花自交结实率低的主要原因。研究选取了两个不同的重瓣荷花品种，即自交率低的‘四季赣山’和自交率高的‘金芙蓉’。细胞学分析结果表明，单核期绒毡层过度降解导致的花粉败育是重瓣荷花自交结实率低的根本原因。随后的转录组分析显示，与绒毡层细胞程序性死亡相关的基因在败育关键时期显著差异表达，进一步验证了其在花药中的特异性表达。研究发现，‘四季赣山’在小孢子发育单核期的表达水平显著高于同期的‘金芙蓉’。的过表达导致绒毡层过早降解，结实率显著降低。这些结果表明，基因调控了重瓣荷花的花粉败育。初步揭示了重瓣荷花结实率低的机制，为培育花、籽兼用的荷花品种提供了理论依据。
