小麦根系构型及抗旱性研究进展

Research Progress on Root System Architecture and Drought Resistance in Wheat

小麦是全球最重要的粮食作物之一,干旱是影响其生长发育最重要的非生物胁迫因子。根系作为作物获取水分和养分的重要器官,直接决定了作物对土壤水分的利用效率。近年来,越来越多的研究表明,根系构型在植物干旱胁迫响应中发挥了重要功能。本文综述了目前根系构型在调控小麦抗旱性方面的研究进展。首先概述了根向性生长,特别是根向重力性生长对植物根系结构的塑造作用,重点总结了目前挖掘到参与根系向重力性生长的相关基因及其分子调控机制,并阐述了根向性生长调控的根系构型是如何介导小麦对干旱胁迫的适应。除了根向性生长,根系的发育过程也参与了对植物根系构型的调控,并决定植物对干旱胁迫的适应能力,因此,本文进一步综述了在干旱胁迫条件下小麦如何通过调控根系发育来改变根系形态,包括增加根长、调控侧根数量和根毛密度等,来增强小麦对土壤水分的吸收和对干旱环境的适应;同时,系统总结了干旱胁迫条件下参与调控作物(尤其是小麦)根系发育的相关基因。此外,根系作为植物地下部分,其构型的解析一直是本领域研究难点,阻碍了对根系结构与植物耐旱性关系的进一步解析,因此,本文也归纳了目前可用于小麦根系二维结构和三维结构表型分析的技术。这些技术可测量和分析小麦根系的长度、密度、生长方向和形态等参数,为深入理解根系构型与小麦抗旱性关系提供技术支撑。最后,展望了改良根系结构在小麦抗旱育种中的应用前景,并对如何挖掘更多潜在的小麦根系构型调控基因,及解析相关基因的调控机理进行了讨论。综上所述,小麦根系结构与小麦抗旱性关系密切,随着测序和分析技术的不断发展,以及小麦根系结构调控机制研究的不断深入,为未来培育抗旱小麦新品种提供了新的手段和策略。

Wheat is the most important cereal crop,and drought is the most significant abiotic stress factor that severely affects wheat growth and development.Plant root system,as a primary organ for crops to acquire water and nutrients,directly determines the efficiency of soil water utilization.In recent years,increasing evidence has shown that plant root system architecture(RSA)plays an important role in plant tolerance to drought stress.This review summarizes the current research progress on the regulation of wheat drought tolerance determined by RSA.First,we present how root tropism especially root gravitropism shapes the RSA,summarize the relevant genes and molecular regulatory mechanism involved in root gravitropic growth,and explain how the root tropism-regulated RSA is implicated in wheat adaptation to drought stress.In addition to root tropic growth,the root development also participates in the RSA formation and the plant adaptability to drought stress.Therefore,this review further summarizes how wheat regulates root development to alter its root system morphology(including increasing root length,modifying lateral root number and root hair density,etc.),thereby enhancing its water acqusition from the soil and its adaption to drought environment.The identified genes involved in wheat root development under drought stress conditions are also systematically summarized.Furthermore,as the underground part of plants,the revelation of RSA has always been a challenging task,which hinders our understanding of the relationship between RSA and plant drought tolerance.Therefore,this review also summarized the available techniques used to analyze the RSA at two-and three-dimension levels.These techniques can measure and analyze wheat root length,density,growth direction,and morphology parameters,laying technical support for an insightful understanding of the relationship between wheat RSA and drought resistance.Finally,we discuss the prospect of the improvement of RSA in breeding wheat drought-resistant varieties,as well as provide an outlook for how to identify genes regulating wheat RSA and pinpoint their regulatory mechanism.In summary,the relationship between wheat RSA and drought resistant is closely associated.The continuous development of sequencing techniques,along with the deepening research on the regulatory mechanism of wheat RSA,will provide new means and strategies for the further breeding of drought-tolerance wheat varieties.