Junping Yu, Jiaojiao Han, Yu-Jin Kim, Ming Song, Zhen Yang, Yi He, Ruifeng Fu, Zhijing Luo, Jianping Hu, Wanqi Liang, and Dabing Zhang

PNAS November 14 2017; vol.114; no.46: 12327-12332

Significance

By affecting male fertility in crops, climate temperature change has a major impact on global food security. Here we show the role of two rice leucine-rich repeat–receptor-like kinases, TMS10 and TMS10L, which redundantly control male fertility under fluctuating temperatures. This finding provides insights into how plants overcome adversary temperature changes to achieve normal male fertility and a new genetic resource for crop hybrid seed production.

Abstract

Plants employ dynamic molecular networks to control development in response to environmental changes, yet the underlying mechanisms are largely unknown. Here we report the identification of two rice leucine-rich repeat receptor-like kinases, Thermo-Sensitive Genic Male Sterile 10 (TMS10) and its close homolog TMS10-Like (TMS10L), which redundantly function in the maintenance of the tapetal cell layer and microspore/pollen viability under normal temperature conditions with TMS10 playing an essential role in higher temperatures (namely, 28 °C). tms10 displays male sterility under high temperatures but male fertility under low temperatures, and the tms10 tms10l double mutant shows complete male sterility under both high and low temperatures. Biochemical and genetic assays indicate that the kinase activity conferred by the intracellular domain of TMS10 is essential for tapetal degeneration and male fertility under high temperatures. Furthermore, indica or japonica rice varieties that contain mutations in TMS10, created by genetic crosses or genome editing, also exhibit thermo-sensitive genic male sterility. These findings demonstrate that TMS10 and TMS10L act as a key switch in postmeiotic tapetal development and pollen development by buffering environmental temperature changes, providing insights into the molecular mechanisms by which plants develop phenotypic plasticity via genotype–environment temperature interaction. TMS10 may be used as a genetic resource for the development of hybrid seed production systems in crops.

See: http://www.pnas.org/content/114/46/12327.full

Figure 1: tms10 displays temperature-dependent male fertility. (A–C) Spikelets at stage 13 after the removal of half of lemma and palea. (Scale bars, 2 mm.) (D–F) Anthers that contain pollen grains stained by I₂-KI. (Scale bars, 200 µm.) (G–I) Semithin section analysis at stage 9, when microspores were released from tetrads. (Scale bars, 20 µm.) (J–L) TEM at stage 9. Shown are the anther wall layers with a focus on tapetal cells. (Scale bars, 5 µm.) DMs, degenerated microspores; E, epidermis; En, endothecium; Ml, middle layer; Ms, microspore; T, tapetum.