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植物雌雄异株性别决定研究进展

花匠小妙招
2024-12-30 15:53

摘要：

植物中雌雄性别分化是一种进化的性状。雌雄异株在多个开花植物谱系中独立演化, 但各个支系的性染色体状态、性别决定区域与性别决定基因不尽相同。多样的植物性染色体和性别决定系统为研究植物性别相关基因的形成机制、性别决定区域和性染色体进化提供了极好的机会。随着测序技术的进步和分析方法的提高, 近年来越来越多物种性别决定的相关分子机制得到解析, 并将理论成果应用于提升经济效益与城市环境等实际问题中。本文将从目前的研究现状和方法, 性别决定单、双基因模型的建立, 植物性染色体进化过程等方面进行总结, 对未来植物性别决定的研究提出四点建议: (1)研究方向逐步从基因研究扩展到调控途径研究; (2)从单一物种转向相关科属比较研究; (3)改进现有性别决定基因模型或探索新模型和性别模式物种; (4)加强性别鉴定技术在实际生产中的研发工作。同时探讨性别决定理论研究未来在农业生产、园艺绿化种植中幼苗性别鉴别筛选等方面的应用前景。

关键词: 雌雄异株, 性别决定, 性染色体, 重组抑制, 双基因模型

Abstract

Background & Aims: Sexual differentiation of plants, also known as dioecy, is the phenomenon of the different female and male reproductive organs in different species and individuals. Dioecious species of flowering plants evolved independently into multiple phylogenetic branches, with each expressing different sex chromosome status, sex determination regions and genes for each branch. In this review, we will summarize the current direction of sex determination research in angiosperms, and appropriately prospect the direction of future research.

Progress: We summarized the formation process of the plant sex determining gene model and the evolution of plant sex chromosomes after conducting a literature review. Two types of mutation models for plant sex determination have been proposed: the ‘two-mutations’ model clarifies that the evolution of sex determination requires two mutations, leading to male sterility and female sterility respectively, while the ‘single-mutation’ model is a single mutant gene that regulates and determines both male and female development of the plant. The diversity of plant sex chromosomes and sex determination systems provides an excellent opportunity to study the formation mechanism of plant sex-related genes, sex determination regions, and sex chromosome evolution. The evolution of plant chromosomes started with a pair of autosomes producing sex-determining gene mutations, forming the initial sex chromosomes. With different selection pressure between female and male plant individuals, the mutant genes were gradually antagonized, and the recombination inhibition was promoted. Accumulation of repeated elements and inhibition of recombination causes the Hill-Robertson effect, which increases the difference between the two chromosomes and eventually leads to the formation of sex chromosomes. The sex chromosomes of some species gradually evolved from homomorphic chromosomes to heteromorphic chromosomes. In this review, sex-determined regions and genes are sorted out and compared in detail according to currently existing characteristics. At present, most studies on the sex-determining regions and genes of angiosperms are carried out by methods such as genome, transcriptome, and resequencing, and the results are primarily in line with the ‘two-mutations’ or ‘single-mutation’ models. Meanwhile, this review further outlines the application of sex determination research in practical production.

Prospects: We propose four suggestions for future research on sex determination in plants: (1) gradually expanding the sight from gene to the regulatory pathways of research; (2) shifting from a single species to research comparisons of related families and genera; (3) improving and exploring current or new sex-determining gene models or sex-model species; and (4) strengthening the identification technology in actual production research and development efforts.

Key words: dioecious plants, sex determination, sex chromosomes, recombination suppression, ‘two-mutations’, model