Efficient identification of palatability-related genes using QTL mapping in rice breeding

The gelatinization temperature of rice is an important factor in determining the eating and cooking quality, and it affects consumer preference. The alkali digestion value (ADV) is one of the main methods used to test the quality of rice and has a high correlation with the gelatinization temperature. For the development of high-quality rice, it is important to understand the genetic basis of palatability-related traits, and QTL analysis is a statistical method linking phenotypic data and genotype data and is an effective method to explain the genetic basis of variation in complex traits. QTL mapping related to the ADV of brown and milled rice was performed using the 120 Cheongcheong/Nagdong double haploid (CNDH) line. As a result, 12 QTLs related to ADV were detected, and 20 candidate genes were selected from the RM588-RM1163 region of chromosome 6 through screening by gene function analysis. The comparison of the relative expression level of candidate genes showed that OsSS1q6 is highly expressed in CNDH lines with high ADV in both brown rice and milled rice. In addition, OsSS1q6 has high homology with the starch synthase 1 protein and interacts with various starch biosynthesis-related proteins, such as GBSSII, SBE, and APL. Therefore, we suggest that OsSS1q6 identified through QTL mapping could be one of the various genes involved in the gelatinization temperature of rice by regulating starch biosynthesis. This study can be used as basic data for breeding high-quality rice and provides a new genetic resource that can increase the palatability of rice.

Automated summary

The gelatinization temperature of rice plays a crucial role in its eating and cooking quality, as well as consumer preference. Alkali digestion value (ADV) is a commonly used method to assess rice quality and is highly correlated with gelatinization temperature. This study utilized QTL analysis to identify genetic factors related to ADV in brown and milled rice. Through this analysis, 12 QTLs related to ADV were identified, and a screening of candidate genes in the chromosome 6 region resulted in the selection of 20 genes. Among these, OsSS1q6 showed a high expression level and has been found to interact with starch biosynthesis-related proteins. Therefore, OsSS1q6 may play a role in regulating the gelatinization temperature of rice through the control of starch biosynthesis. This study provides valuable insights for breeding high-quality rice and offers a new genetic resource for improving rice palatability.