Flowering is a crucial process in the growth and development of plants, playing an essential role in their life cycles. Thus, research into the regulation of flowering time holds significant importance. While CmBBX7 has been identified as a flowering activator regulated by photoperiod, the molecular mechanisms underlying its regulation at the protein level remain unclear. In this study, we utilized yeast two-hybrid screening to identify two proteins that interact with CmBBX7: the phosphatase CmPP6 and the E3 ubiquitin ligase CmMIEL1. Ubiquitination assays confirmed that CmMIEL1 promotes the degradation of CmBBX7, thereby affecting its protein stability and influencing flowering. Genetic evidence indicated that both CmPP6 and CmMIEL1 delay flowering. By interacting with CmBBX7, they indirectly repress the expression of CmFTL1, which is a key flowering gene in chrysanthemum. Our findings provide preliminary evidence that ubiquitin modification affects the stability of the CmBBX7 protein and thereby regulates flowering in chrysanthemum.
Yuqing Zhu, Jinyu Jin, Yiwen Zhai et al.· Plant physiology and biochem...· 0 citations
Black spot disease (BSD), caused by Alternaria alternata, is a devastating threat to the chrysanthemum industry, yet its genetic basis remains largely elusive. The present study aimed to decipher the genetic architecture of chrysanthemum BSD resistance and to discover genetic loci and candidate genes using genome-wide association studies (GWAS) in a biparental F1 population (n = 164). Phenotypic evaluations of BSD resistance were conducted using both multi-stage detached-leaf assays and seedling-stage in vivo inoculations. The disease severity index (DSI) exhibited wide coefficient of variation (CV: 26.21%–54.84%) and high broad-sense heritability (0.71–0.95), with significant transgressive segregation observed in the F1 progeny. 375 865 high-quality SNPs-based GWAS identified 220 quantitative trait nucleotides (QTNs) and 36 QTN-by-environment interactions (QEIs), explaining up to 7.39% and 3.46% of the phenotypic variance, respectively. Among 26 stable QTNs, 17 favorable alleles displayed significant additive effects and a clear dosage-pyramiding effect (P < 0.001). By integrating functional annotation with transcriptome profiling, 34 candidate genes involved in immune defense were identified within the candidate intervals. Notably, three key candidate genes, CmABF1, CmSINAT3, and CmLTPG1, were validated as positive regulators of BSD resistance through transient overexpression and silencing assays. The research findings provide crucial genetic resources for the molecular improvement of resistance to BSD in chrysanthemums.
Ying Li, X. Chen, Xinjing Lai et al.· Horticulture Research· 0 citations
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