Seed germination and dormancy: The classic story, new puzzles, and evolution

摘要

This review highlights recent progresses in seed germination and dormancy research.Research on the weakening of the endosperm during germination,which is almost a classic theme in seed biology,was resumed byα-xylosidase studies.Strong genetic evidence was presented to suggest that the quality control of xyloglucan biosynthesis in the endosperm(and the embryo)plays a critical role in germination.Further analyses on the endosperm and the adjace nt layers have suggested that the cutin coat in the endosperm-testa interphase negatively affects germination while the en dosperm-embryo in terphase produces a sheath that facilitates germination.These progresses significantly advanced our understanding of seed germination mechanisms.A breakthrough in dormancy research,on the other hand,revealed the unique abscisic acid signaling pathway that is regulated by DELAY OF GERMINATION1(DOG1).The detailed analysis of DOC1 expression uncovered the intriguing story of reciprocal regulation of the sensean tisense pair,which gen erated new questions.Recent studies also suggested that the DOG1 function is not limited to dormancy but extended through general seed maturation,which provokes questions about the evolution of DOG1 family proteins.Seed biology is becoming more exciting with the classic stories being revitalized and new puzzles emerging from the frontier.