Regulation of anthocyanin accumulation in rice (<i>Oryza sativa</i> L. subsp. <i>indica</i>) using MgSO₄ spraying and low temperature

<p>Pericarp pigmented grains of rice have been reported as anthocyanin enriched source of antioxidants. The aim of this investigation was to regulate anthocyanin accumulation in pericarp pigmented rice cv. ‘Hom Nil’ using 0, 10, 50, and 100 mM MgSO₄ foliar spray. The level of magnesium content in the leaf tissues treated with 100 mM MgSO₄ for 2 d increased 2.6 times over control (0 mM MgSO₄). After growing the treated plants under 16°C for 28 d, photosynthetic abilities were reduced by 17−93%, leading to retarded plant height (39−42% less than control). In addition, grain yield per panicle of the plants grown under 16°C for 28 d was reduced by 26−75% compared to the plants grown under 32°C.Total anthocyanin concentration, cyanidin-3-glucoside and peonidin-3-glucoside in the pericarp of the grains derived from the rice treated with 100 mM MgSO₄ was increased 3.8 times over the control. Peonidin-3-glucoside, a dominant compound was reported for the first time. The study concludes that Mg−enrichment may play a key role as a metalloid in stabilizing anthocyanin, a secondary metabolite in the leaf sheath tissues and pericarp of grains in ‘Hom Nil’ rice cultivar.</p

Data_Sheet_1_Determination of traits responding to iron toxicity stress at different stages and genome-wide association analysis for iron toxicity tolerance in rice (Oryza sativa L.).zip

Rice is the staple food for more than half of the world’s population. Iron toxicity limits rice production in several regions of the world. Breeding Fe-tolerant rice varieties is an excellent approach to address the problem of Fe toxicity. Rice responds differently to Fe toxicity at different stages. Most QTLs associated with Fe toxicity have been identified at the seedling stage, and there are very few studies on Fe toxicity across different stages. In this study, we investigated agro-morphological and physiological traits in response to Fe toxicity in a rice diversity panel at seedling, vegetative, and reproductive stages and applied GWAS to identify QTLs/genes associated with these traits. Among agro-morphological and physiological parameters, leaf bronzing score (LBS) is a key parameter for determining Fe toxicity response at all stages, and SDW could be a promising parameter at the seedling stage. A total of 29 QTLs were identified on ten chromosomes. Among them, three colocalized QTLs were identified on chromosome 5, 6, and 11. Several QTLs identified in this study overlapped with previously identified QTLs from bi-parental QTL mapping and association mapping. Two genes previously reported to be associated with iron homeostasis were identified, i.e., LOC_Os01g72370 (OsIRO2, OsbHLH056) and LOC_Os04g38570 (OsABCB14). In addition, based on gene-based haplotype analysis, LOC_Os05g16670 was identified as a candidate gene for the colocalized QTL on chromosome 5 and LOC_Os11g18320 was identified as a candidate gene for the colocalized QTL on chromosome 11. The QTLs and candidate genes identified in this study could be useful for rice breeding programs for Fe toxicity tolerance.</p