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The cultivated strawberry (Fragaria × ananassa Duch.) is an important horticultural crop. The economic values of strawberry cultivars are decided by their fruit qualities including taste, color and aroma. The important role of MYB transcription factors in fruit quality regulation is recognized increasingly with the identification of MYB genes involved in metabolism. A total of 407 MYB genes of F. × ananassa (FaMYBs) were identified in the genome-wide scale and named according to subgenome locations. The 407 FaMYBs were clustered into 36 groups based on phylogenetic analysis. According to synteny analysis, whole genome duplication and segmental duplication contributed over 90% of the expansion of the FaMYBs family. A total of 101 FaMYB loci with 1–6 alleles were identified by the homologous gene groups on homologous chromosomes. The differentially expressed FaMYB profiles of three cultivars with different fruit quality and fruit ripe processes provided the 8 candidate loci involved in fruit quality regulation. In this experiment, 7, 5, and 4 FaMYBs were screeded as candidate genes involved in the regulation of metabolism/transportation of anthocyanins, sugars or organic acids and 4-hydroxy-2, 5-dimethyl-3(2H)-furanone, respectively. These results pointed out the key FaMYBs for further functional analysis of gene regulation of strawberry fruit quality and would be helpful in the clarification on ofe roles of MYBs in the metabolism of fruit crops. [ABSTRACT FROM AUTHOR]

Background: Cadmium (Cd) is a toxic heavy metal that is harmful to the environment and human health. Cd pollution threatens the cultivation of rice (Oryza sativa L.) in many countries. Improving rice performance under Cd stress could potentially improve rice productivity. Results: In this study, 9 growth traits of 188 different cultivated rice accessions under normal and Cd stress conditions were found to be highly variable during the seedling stage. Based on ~3.3 million single nucleotide polymorphisms (SNPs), 119 Cd-mediated growth response (CGR) quantitative trait loci (QTL) were identified by a genome-wide association study (GWAS), 55 of which have been validated by previously reported QTL and 64 were new CGR loci. Combined with the data from the GWAS, transcriptome analysis, gene annotations from the gene ontology (GO) Slim database, and annotations and functions of homologous genes, 148 CGR candidate genes were obtained. Additionally, several reported genes have been found to play certain roles in CGRs. Seven Cd-related cloned genes were found among the CGR genes. Natural elite haplotypes/alleles in these genes that increased Cd tolerance were identified by a haplotype analysis of a diverse mini core collection. More importantly, this study was the first to uncover the natural variations of 5 GST genes that play important roles in CGRs. Conclusion: The exploration of Cd-resistant rice germplasm resources and the identification of elite natural variations related to Cd-resistance will help improve the tolerance of current major rice varieties to Cd, as well as provide raw materials and new genes for breeding Cd-resistant varieties. [ABSTRACT FROM AUTHOR]

The low seedling rate of rice caused by submergence in the process of rice direct seeding has always been an important factor limiting the popularization of rice direct seeding technology. Improving the tolerance of rice to submergence stress will benefit the production of rice and the promotion of direct seeding technology. In this study, we determined the submergence coleoptile length (SCL), submergence shoot length (SSL), and submergence tolerance index (STI) of 166 different cultivated rice seedlings as the phenotypes. Through the genome-wide association analysis (GWAS) of SCL, SSL, and STI, we found multiple quantitative trait locus (QTL) locations, including nine reported QTL locations. To narrow down the candidate gene numbers, we combined data from GWAS, transcriptomic analysis, gene function annotation, and reported QTL locations, and 50 candidate genes for submergence stress were obtained. Some reported genes had been firstly found to play certain roles in submergence-mediated growth response. Combining with reported RNA-seq data and expression profile data, we focused on four adjacent genes (LOC_Os11g47550, LOC_Os11g47570, LOC_Os11g47590, and LOC_Os11g47610) located in qAG11. RNA-seq and expression profile suggested the expression of these genes in sensitive and tolerant types differs hundreds of times (146~510 fold). Based on the diverse germplasms, we determined the natural haplotype of these genes. The haplotype analysis of these four genes showed a large genetic difference between indica and japonica. These results help us to better understand the molecular mechanism of natural variations in submergence tolerance among diverse germplasms and provide materials and new genes for further selection of new submergence tolerance varieties. [ABSTRACT FROM AUTHOR]