The Rice Small Auxin-Up RNA Gene OsSAUR33 Regulates Seed Vigor via Sugar Pathway during Early Seed Germination.

Jia Zhao,Yongqi He,Zhibo Huang,Zhoufei Wang,Shan Sun,Wenjun Li,Liling Peng

doi:10.3390/ijms22041562

Jia Zhao, Yongqi He + Show 5 more

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https://doi.org/10.3390/ijms22041562

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Abstract

Seed vigor affects seed germination and seedling emergence, and therefore is an important agronomic trait in rice. Small auxin-up RNAs (SAURs) function in a range of developmental processes, but their role in seed vigor remains unclear. Here, we observed that disruption of OsSAUR33 resulted in reduced germination rates and low seed uniformity in early germination. Expression of OsSAUR33 was higher in mature grains and early germinating seeds. RNA-seq analysis revealed that OsSAUR33 modulated seed vigor by affecting the mobilization of stored reserves during germination. Disruption of OsSAUR33 increased the soluble sugar content in dry mature grains and seeds during early germination. OsSAUR33 interacted with the sucrose non-fermenting-1-related protein kinase OsSnRK1A, a regulator of the sugar signaling pathway, which influences the expression of sugar signaling-related genes during germination. Disruption of OsSAUR33 increased sugar-sensitive phenotypes in early germination, suggesting OsSAUR33 likely affects seed vigor through the sugar pathway. One elite haplotype of OsSAUR33 associated with higher seed vigor was identified mainly in indica accessions. This study provides insight into the effects of OsSAUR33 on seed vigor in rice.

Highlights

Rice (Oryza sativa L.) is one of the most important food crops in the world
We identified 48 OsSAUR genes based on their typical auxin-inducible domain in rice
This is fewer OsSAUR genes than the 58 OsSAUR members identified in a previous study [28] because of the updated data and more stringent criteria used in our study

Summary

Introduction

Rice (Oryza sativa L.) is one of the most important food crops in the world. Direct seeding of rice has become popular in China and South Asia over the past three decades due to its low cost and operational simplicity [1,2]. There are some issues with direct seeding compared with transplanting, such as poor seedling establishment and challenges with weed competition. Seeds with high vigor have rapid germination, good seedling establishment, and vigorous seedling growth [3,4]. Good seedling establishment is very important in direct seeding of rice for establishing sufficient numbers of plants and for yield [5]. Cloning seed vigor-related genes in rice and elucidating their molecular mechanisms may have applications in breeding programs

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