Yiwen Xu, Siming Chen, Mingming Xue, Xingyu Chen, Zhibo Liu, Xuefeng Wei, Ji-Ping Gao & Chen Chen

Theoretical and Applied Genetics May 2023; vol. 136, Article number: 117

Published 24 April 2023

Fig. 3.35. Light micrographs of the outer part of the grain of wheat cv. Crousty, showing the aleurone and subaleurone regions. A, stained with acid fuchsin and Calcofluor to show proteins and cell walls, respectively. Sections were examined using an Olympus BX-50 microscope (epifluorescence, excitation 400–410 nm, emission >500 nm). Acid fuchsin stains protein red, while β-glucans present in cell walls show blue fluorescence with Calcofluor. Unstained starch appears black. B, stained for protein and starch with light green and iodine (observed using bright-field microscopy). Light green stains protein green, while iodine stains the amylose component of starch blue and amylopectin brown.

(Courtesy VTT Technical Research Centre of Finland)  Bechtel DB et al 2009

Key message

Mapping of QTLs for dorsal aleurone thickness (DAT) was performed using chromosome segment substitution lines in rice. Three QTLs, qDAT3.1, qDAT3.2, and qDAT7.1, were detected in multiple environments.

Abstract

As a specified endosperm cell type, the aleurone has an abundance of various nutrients. Increasing the number of aleurone layers is a practicable way of developing highly nutritious cereals. Identifying genes that can increase aleurone thickness is useful for the breeding of aleurone traits to improve the nutritional and health values of rice. Here, we found that iodine staining could efficiently distinguish the aleurone layers, which revealed great variation of the aleurone thickness in rice, especially at the dorsal side of the seed. Therefore, we used a population of chromosome segmental substitution lines (CSSLs) derived from Koshihikari and Nona Bokra for quantitative trait locus (QTL) analysis of the dorsal aleurone thickness (DAT). Three QTLs, qDAT3.1, qDAT3.2, and qDAT7.1, were detected in multiple seasons. Among these, qDAT3.2 colocalizes with Hd6 and Hd16, two QTLs previously identified to regulate the heading date of Koshihikari, explaining the negative correlation between the DAT and days to heading (DTH) in rice. We also provide evidence that early-heading ensures the filling of rice seed under a relatively high temperature to promote aleurone thickening. qDAT7.1, the most stable QTL expressed in different environments, functions independently from heading date. Although Nona Bokra has a lower DAT, its qDAT7.1 allele significantly increased DAT in rice, which was further validated using two near-isogenic lines (NILs). These findings pave the way for further gene cloning of aleurone-related QTLs and may aid the development of highly nutritious rice.

See https://link.springer.com/article/10.1007/s00122-023-04368-0