The effects and mechanisms of salicylic acid (SA) on defense response to Colletotrichum gloeosporioides from mango fruits were investigated by in vitro and in vivo test. In vitro experiment results showed that SA significantly reduced mycelial growth of C. gloeosporioides in a concentration‐dependent manner. SA effectively controlled anthracnose decay on inoculated mango fruit, as well as natural infection. Disease incidence and lesion diameter in SA‐treated fruit were significantly lower than those of the control fruit. SA treatment increased the activities of chitinase, β‐1,3‐glucanase, phenylalanine ammonia‐lyase and polyphenoloxidase, and the content of total phenolic compounds and lignin in mango fruit. Moreover, SA treatment effectively maintained fruit firmness by suppressing conversion of insoluble protopectin into water soluble pectin. And correlation analysis showed there is a higher negative correlation between fruit firmness and disease incidence. These findings suggest that the effect of SA on postharvest diseases was attributed to its direct antimicrobial activity and the elicitation of resistant responses, as well maintaining the firmness in mango fruit. Therefore, SA treatment is a promising measure for controlling postharvest anthracnose rot in mango. Practical Applications Induction of fruit resistance against pathogenic infection with biological or chemical elicitors has been thought to be a promising approach for controlling of postharvest diseases and reducing the use of synthetic fungicides. Anthracnose, caused by Colletotrichum gloeosporioides is the predominant postharvest disease in mango production that causes severe postharvest losses and fruit quality deterioration. SA is a natural plant substance involved in plant defense responses to biotic stresses. The present results from in vitro and in vivo experiment suggested that SA treatment could effectively inhibit mycelial growth of C. gloeosporioides, enhance resistance of mango fruit against the pathogen and reduce anthracnose rot, as well maintain fruit firmness. Hence, SA can be applied in mango storage and preservation.

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Background The transition from the vegetative to reproductive growth is an important stage in radish life cycle (Raphanus sativus L.). However, the molecular mechanism of radish bolting and flowering is still unclear. To obtain new insight into the genomic variation, population structure, genetic diversity and molecular regulation mechanism of flowering time, genome resequencing and transcriptome sequencing were conducted between two cultivars with extreme differences in flowering time. Results In this study, a total of 366,679 single nucleotide polymorphisms (SNPs) and 97,973 insertion-deletion (InDel) markers were identified based on genome sequences between ‘YZH’ and ‘XHT’. In all, 53,343 SNPs and 4,257 InDels were detected in two cultivars by transcriptome. Among the InDel variations, 85 genomic and 15 transcriptomic InDels were newly developed and validated PCR. Population structure and phylogenetic relationship revealed that the radish cultivars from northern China were clustered together and the southwest China cultivars were clustered together. RNA-Seq analysis revealed that 10,983 differentially expressed genes (DEGs) were identified between the two cultivars, of which 5,020 were upregulated and 5,983 were downregulated. In total, 145 flowering time-related DGEs were detected, most of which were involved in flowering time integrator, circadian clock/photoperiod autonomous, and vernalization pathways. In flowering time-related DGEs region, 150 transcriptomic SNPs and 9 InDels were obtained. RT-qPCR displayed that the expression pattern of ten DEGs were consistent with the results obtained by RNA-Seq analysis. Conclusions The large amount of SNPs and InDels identified in this study will provide a valuable marker resource for radish genetic and genomic studies. The detected flowering time-related DGEs could provide fundamental insight into bolting and flowering regulatory networks and accelerate further investigating molecular mechanisms underlying the transition from vegetative to reproductive growth in radish.

Background Single nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) are the most abundant genetic variations and widely distribute across the genomes in plant. Development of SNP and InDel markers is a valuable tool for genetics and genomic research in radish (Raphanus sativus L.). Results In this study, a total of 366,679 single nucleotide polymorphisms (SNPs) and 97,973 insertion-deletion (InDel) markers were identified based on genome resequencing between ‘YZH’ and ‘XHT’. In all, 53,343 SNPs and 4,257 InDels were detected in two cultivars by transcriptome sequencing. Among the InDel variations, 85 genomic and 15 transcriptomic InDels were newly developed and validated PCR. The 100 polymorphic InDels markers generated 207 alleles among 200 Chinese radish germplasm, with an average 2.07 of the number of alleles (Na) and with an average 0.33 of the polymorphism information content (PIC). Population structure and phylogenetic relationship revealed that the radish cultivars from northern China were clustered together and the southwest China cultivars were clustered together. RNA-Seq analysis revealed that 11,003 differentially expressed genes (DEGs) were identified between the two cultivars, of which 5,020 were upregulated and 5,983 were downregulated. In total, 145 flowering time-related DGEs were detected, most of which were involved in flowering time integrator, circadian clock/photoperiod autonomous, and vernalization pathways. In flowering time-related DGEs region, 150 transcriptomic SNPs and 9 InDels were obtained. Conclusions The large amount of SNPs and InDels identified in this study will provide a valuable marker resource for radish genetic and genomic studies. The SNPs and InDels within flowering time-related DGEs provide fundamental insight into for dissecting molecular mechanism of bolting and flowering in radish.

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