Essential roles of autophagy in metabolic regulation in endosperm development during rice seed maturation

Abstract

Autophagy plays crucial roles in the recycling of metabolites, and is involved in many developmental processes. Rice mutants defective in autophagy are male sterile due to immature pollens, indicating its critical role in pollen development. However, physiological roles of autophagy during seed maturation had remained unknown. We here found that seeds of the rice autophagy-deficient mutant Osatg7-1, that produces seeds at a very low frequency in paddy fields, are smaller and show chalky appearance and lower starch content in the endosperm at the mature stage under normal growth condition. We comprehensively analyzed the effects of disruption of autophagy on biochemical properties, proteome and seed quality, and found an abnormal activation of starch degradation pathways including accumulation of α-amylases in the endosperm during seed maturation in Osatg7-1. These results indicate critical involvement of autophagy in metabolic regulation in the endosperm of rice, and provide insights into novel autophagy-mediated regulation of starch metabolism during seed maturation.

Autophagy: An Intracellular Degradation Pathway Regulating Plant Survival and Stress Response

“…The rice Osatg7-1 mutant also produces smaller seeds with a chalky appearance and lower starch content. During seed maturation of Osatg7-1, the starch degradation pathways are activated abnormally in the endosperm, indicating that autophagy plays critical roles in metabolic regulation in the endosperm (Sera et al, 2019).…”

Genome-wide Identification and Expression Analysis of Autophagy-related Genes (ATGs) in Medicago Truncatula

“…Seed development consists of embryo morphogenesis and seed maturation [43]. In rice, autophagy has been shown to be involved in the regulation of starch and sugar metabolism during seed maturation [44]. In Norway spruce (Picea abies), autophagy is also involved in embryogenesis in which it regulates vacuolar cell death of the embryo suspensor [45].…”

Degradation of Lipid Droplets in Plants and Algae—Right Time, Many Paths, One Goal

“…Autophagy is a highly conserved process involved in regulation of intracellular degradation and recycling of individual molecules as well as whole organelles, via lysosomes in animals or vacuoles in yeast and plants (Avin-Wittenberg et al, 2012;Bento et al, 2016;Marshall and Vierstra, 2018;Couso et al, 2018). In plants, autophagy plays an important role in many developmental processes, such as seed development (Di Berardino et al, 2018;Sera et al, 2019) and leaf senescence (Avila-Ospina et al, 2014;Li et al, 2014). Autophagy is highly induced by various abiotic stresses, including nutrient deprivation (Sun et al, 2018;Janse van Rensburg et al, 2019), drought (Bao et al, 2020), and biotic stresses e.g.…”