Male sterile 305 Mutation Leads the Misregulation of Anther Cuticle Formation by Disrupting Lipid Metabolism in Maize.

Haichun Shi,Chenxi Feng,Jichao Yuan,Yu Fu,Ronghuan Gu,Qun Sun,Xuejie Yu,Yang Yu,Yongpei Ke

doi:10.3390/ijms21072500

Abstract

The anther cuticle, which is mainly composed of lipid polymers, functions as physical barriers to protect genetic material intact; however, the mechanism of lipid biosynthesis in maize (Zea mays. L.) anther remains unclear. Herein, we report a male sterile mutant, male sterile 305 (ms305), in maize. It was shown that the mutant displayed a defective anther tapetum development and premature microspore degradation. Three pathways that are associated with the development of male sterile, including phenylpropanoid biosynthesis, biosynthesis of secondary metabolites, as well as cutin, suberine, and wax biosynthesis, were identified by transcriptome analysis. Gas chromatography-mass spectrometry disclosed that the content of cutin in ms305 anther was significantly lower than that of fertile siblings during the abortion stage, so did the total fatty acids, which indicated that ms305 mutation might lead to blocked synthesis of cutin and fatty acids in anther. Lipidome analysis uncovered that the content of phosphatidylcholine, phosphatidylserine, diacylglycerol, monogalactosyldiacylglycerol, and digalactosyldiacylglycerol in ms305 anther was significantly lower when compared with its fertile siblings, which suggested that ms305 mutation disrupted lipid synthesis. In conclusion, our findings indicated that ms305 might affect anther cuticle and microspore development by regulating the temporal progression of the lipidome in maize.

Highlights

Maize is a monoecious plant with separate male and female flowers growing on the same plant
When compared with the normal K305F anthers, we found that the anthers of ms305 failed in extruding from the spikelet, and no pollen grain was produced inside anthers, leaving an empty shell (Figure 1)
The abortion characteristics of Ms33, which showed no difference in anatomical structure or meiotic events in the fertile and sterile plants before the tetrad stage, as well as the severe degradation of the tapetum in sterile plants at the early uninucleate stage [39], were completely opposite to those of ms305, which delay the degradation of tapetum at this stage

Summary

Introduction

Maize is a monoecious plant with separate male and female flowers growing on the same plant. Detasseling of the female inbred parent is widely employed by the seed industry to produce hybrid seed [1]. Mechanical detasseling is effective in maize hybrid seed production, it is time-consuming and labour-intensive [2]. Damage to the top leaves during detasseling reduces the hybrid seed yield [3]. Male sterility is the most efficient way to ensure cross-pollination [4,5]. Nuclear genes, mainly those that affect tapetum or microspore development in flowering plants, control genetic male sterility (GMS), which is stable in different germplasms and growth environments [6].

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Discussion

Conclusion