Effects of Wx Genotype, Nitrogen Fertilization, and Temperature on Rice Grain Quality

Abstract

Quality is a complex trait that is not only the key determinant of the market value of the rice grain, but is also a major constraint in rice breeding. It is influenced by both genetic and environmental factors. However, the combined effects of genotypes and environmental factors on rice grain quality remain unclear. In this study, we used a three-factor experimental design to examine the grain quality of different Wx genotypes grown under different nitrogen fertilization and temperature conditions during grain development. We found that the three factors contributed differently to taste, appearance, and nutritional quality. Increased Wx function and nitrogen fertilization significantly reduced eating quality, whereas high temperature (HT) had almost no effect. The main effects of temperature on appearance quality and moderate Wx function at low temperatures (LTs) contributed to better appearance, and higher nitrogen fertilization promoted appearance at HTs. With regard to nutritional quality, Wx alleles promoted amylose content (AC) as well as starch-lipids content (SLC); nitrogen fertilization increased storage protein content (PC); and higher temperature increased lipid content but decreased the PC. This study helps to broaden the understanding of the major factors that affect the quality of rice and provides constructive messages for rice quality improvement and the cultivation of high-quality rice varieties.

A Novel Allele in the Promoter of Wx Decreases Gene Expression and Confers Lower Apparent Amylose Contents in Japonica Rice (Oryza sativa L.)

“…It can increase yield, but it also decreases the ECQ of rice [ 18 ]. With the increase through nitrogen fertilizers, the AC of rice decreased [ 17 ]. Thus, we still know less about the relationship between Wx of the key controlling AC gene and nitrogen.…”

“…The homozygous T2 lines were used for expression detection and trait collection. The copy number of the transgene in the transgenic rice plants was determined using real-time PCR according to Zhang et al [ 17 ]. The primers are listed in Table S3 .…”

“…Nitrogen plays a pivotal role in AC regulation in rice, and AC tends to increase under low-nitrogen conditions [ 17 , 18 ]. The glutamine synthetase (OsGS1;1) enzyme is crucial for nitrogen use efficiency (NUE), and the alternative splicing of OsGS1;1 affects the AC in rice [ 19 ].…”

“…Moreover, the application of nitrogen fertilizer reduced the AC in the rice grain. Achieving an optimal level of nitrogenous fertilization while maintaining good rice quality poses future challenges [ 17 ]. Therefore, it is vital that researchers identify the possible genetic sites that could be used to balance NUE and good quality.…”

Orchestrating seed storage protein and starch accumulation toward overcoming yield–quality trade‐off in cereal crops

“…Wx encodes GBSSI, which controls the synthesis of amylose, and is the primary determinant of rice eating, cooking and appearance quality (Zhang et al, 2021a; Zhou et al, 2021). Some studies showed that Wx plays a major role in determining storage protein content and flour color (Tan et al, 2001; Xia et al, 2022). How Wx modulates storage protein content remains unknown.…”