种子微生物生态学研究进展

植物种子微生物生态学是研究与种子相联合的微生物的组成﹑功能﹑演替、它们之间关系及其与宿主之间相互关系的科学。种子中蕴含着丰富的微生物资源,它们对种子以及植物的健康具有重要的影响。不同种类植物种子联合的微生物群落由于受到种子本身及外界环境因素的影响而有所差异。论述了种子微生物生态学的概念、主要研究方法、种子微生物生态系统中的微生物种类、相关影响因素,以及种子微生物生态学研究的发展方向。种子微生物生态学的研究对生产实践有重要意义,同时也将丰富种子生物学的内容,对种子科学的发展起到促进作用。

Advances in plant seed-associated microbial ecology

Manymicroorganisms can be found in seeds, and they can affect the health of the seeds as well as the developing plants. The study of seed microbial ecology focuses on plant seed-associated microbial community composition, their function, succession dynamics and the interactions between microorganisms and plants. In this review, we introduce the advances that have been made in this field, including key concepts, the main types of microorganisms, research methods, and physiological and environmental factors that are important for the plant seed microbial community. Research has used culture-independent methods based on molecular biotechnology, combined with traditional culture-dependent methods. The nutrient composition of seeds, which includes sugars, fats and proteins, is important for microorganism growth. Certain nutrient components may attract microorganisms to colonize inside or on the exterior of seeds. Microbial groups, such as bacteria, actinomycetes and fungi, have been found in seeds of some plant species. By 2004, more than 100 species and 50 genera of bacteria had been found in the seeds of plant species, such as Hordeum vulgare, Oryza sativa, Zea mays, Setaria italic, Glycine max, Brassica napus, Gossypium spp., and some trees species. More than 180 species and 70 genera of fungi have been found in crop species, such as Sorghum bicolor, Cicer arietinum, Cajanus cajan and Arachis hypogaea. Most of these fungi have been reported to be seed pathogens. Microbial communities can be affected by seed shape, and it has proved to be more difficult to isolate bacteria from hard, waxy seeds than from normal seeds. Seeds with different nutrient compositions harbor different microbial communities. Dynamic changes of the microbial community could be linked with changes in seed nutrient composition that occur in the developing seed. Different parts of the seed, such as the embryo, endosperm and seed coat, can harbor different specialized microbial communities. Furthermore, particular seed genotypes are associated with particular microbial community structures and activities. The spermosphere, a dynamic microbial succession zone surrounding the germinating seed, is strongly affected by seed exudations and the soil microorganism communities, and is an important part of seed microbial ecology. We conclude our review by proposing future research areas in seed-associated microbial ecology. This includes gaining a more detailed knowledge of specific plant seed-associated microbial communities, as well as a greater understanding the relationship between internal seed conditions, external environmental conditions and the microbial activity. Further study should also focus on the mechanisms underlying seed-microorganism interactions, and consider the application of molecular biotechnology and biometrics in seed microbial ecology.