A point mutation in LTT1 enhances cold tolerance at the booting stage in rice

• Published in: Plant, cell and environment Vol. 43; no. 4; pp. 992 - 1007
• Main Authors: Xu, Yufang, Wang, Ruci, Wang, Yueming, Zhang, Li, Yao, Shanguo
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.04.2020; Wiley Subscription Services, Inc
• Subjects: abortion (plants); Accumulation; Adaptability; Anthers; Apoptosis; Apoptosis - genetics; Apoptosis - physiology; booting stage; breeding programs; Cell death; Cold; cold stress; Cold Temperature; Cold tolerance; Degradation; Gene expression; Genes; Genes, Plant - genetics; Genes, Plant - physiology; Genetic resources; In Situ Nick-End Labeling; LTT1; Microscopy, Electron, Scanning; Mutants; Mutation; Original; Oryza - genetics; Oryza - metabolism; Oryza - physiology; Oryza - ultrastructure; Oryza sativa; Peroxidases - metabolism; Plant breeding; Point mutation; Point Mutation - genetics; Pollen; programmed cell death; proteins; Quantitative Trait, Heritable; Reactive oxygen species; Reactive Oxygen Species - metabolism; Rice; ROS acclimation; seed set; Superoxide Dismutase - metabolism; temperature; Temperature tolerance; booting stage; cold tolerance; rice; ROS acclimation; LTT1
• ISSN: 0140-7791; 1365-3040; 1365-3040
• DOI: 10.1111/pce.13717

The cold tolerance of rice at the booting stage is a main factor determining sustainability and regional adaptability. However, relatively few cold tolerance genes have been identified that can be effectively used in breeding programmes. Here, we show that a point mutation in the low‐temperature tolerance 1 (LTT1) gene improves cold tolerance by maintaining tapetum degradation and pollen development, by activation of systems that metabolize reactive oxygen species (ROS). Cold‐induced ROS accumulation is therefore prevented in the anthers of the ltt1 mutants allowing correct development. In contrast, exposure to cold stress dramatically increases ROS accumulation in the wild type anthers, together with the expression of genes encoding proteins associated with programmed cell death and with the accelerated degradation of the tapetum that ultimately leads to pollen abortion. These results demonstrate that appropriate ROS management is critical for the cold tolerance of rice at the booting stage. Hence, the ltt1 mutation can significantly improve the seed setting ability of cold‐sensitive rice varieties under low‐temperature stress conditions, with little yield penalty under optimal temperature conditions. This study highlights the importance of a valuable genetic resource that may be applied in rice breeding programmes to enhance cold tolerance. Understanding how rice plants respond to the changing environmental temperature is one of the most important biological subjects. By functional analysis of the cold tolerant ltt1 mutant, we demonstrate that acclimation to high endogenous reactive oxygen species level is critical for rice plants to cope with the coming low‐temperature stress. Our results provide a novel strategy for genetic improvement of booting stage cold tolerance in rice.