Zheng Wang, Jian Li, Shaoxia Chen, Yanfang Heng, Zhuo Chen, Jing Yang, Kuanji Zhou,Jiawei Pei, Hang He, Xing Wang Deng, and Ligeng Ma

PNAS November 21 2017; vol.114; no.47: 12614–12619

Significance

Heterosis provides an important strategy for increasing crop yield, and breeding and adoption of hybrid crops is a feasible way to increase crop yields. Male sterility is an essential trait in hybrid seed production for monoclinous crops, including wheat. Heterosis in wheat was observed approximately 100 y ago. However, very little commercial hybrid wheat is planted in the world because of the lack of a suitable male sterility trait. Therefore, understanding the molecular nature of male fertility in wheat is critical for hybrid wheat development. Here, we report the cloning and molecular, biochemical, and cell-biological characterizations of Male Sterility 1 (Ms1) in bread wheat, and provide a foundation for large-scale commercial hybrid wheat breeding and hybrid seed production.

Abstract

Male sterility is an essential trait in hybrid seed production for monoclinous crops, including rice and wheat. However, compared with the high percentage of hybrid rice planted in the world, little commercial hybrid wheat is planted globally as a result of the lack of a suitable system for male sterility. Therefore, understanding the molecular nature of male fertility in wheat is critical for commercially viable hybrid wheat. Here, we report the cloning and characterization of Male Sterility 1 (Ms1) in bread wheat by using a combination of advanced genomic approaches. MS1 is a newly evolved gene in the Poaceae that is specifically expressed in microsporocytes, and is essential for microgametogenesis. Orthologs of Ms1 are expressed in diploid and allotetraploid ancestral species. Orthologs of Ms1 are epigenetically silenced in the A and D subgenomes of allohexaploid wheat; only Ms1 from the B subgenome is expressed. The encoded protein, Ms1, is localized to plastid and mitochondrial membranes, where it exhibits phospholipid-binding activity. These findings provide a foundation for the development of commercially viable hybrid wheat.

See: http://www.pnas.org/content/114/47/12614.full

Figure 4: Subcellular localization of Ms1 and its colocalization with organelle markers. Onion epidermal cells were transiently cotransformed with constructs encoding Ms1-GFP and mCherry-fused organelle markers driven by the 35S promoter. GmMan1, Golgi marker; pFAγ, mitochondria marker; PST1, peroxisome marker; WxTP, plastid marker. (Scale bars: A, 5 µm; and B, 1 μm.)