| Abstrakt: |
Flowering time is an important agronomic trait that contributes to fitness in plants. However, the genetic basis of flowering time has not been extensively studied in pepper. To understand the genetics underlying flowering time, we constructed an F2population by crossing a spontaneous early flowering mutant and a late-flowering pepper line. Using bulked segregant RNA-seq, a major locus controlling flowering time in this population was mapped to the end of chromosome 2. An APETALA2(AP2) homolog (CaFFN) cosegregated with flowering time in 297 individuals of the F2population. A comparison between the parents revealed a naturally occurring rare SNP (SNP2T > C) that resulted in the loss of a start codon in CaFFNin the early flowering mutant. Transgenic Nicotiana benthamianaplants with high CaFFNexpression exhibited a delay in flowering time and floral patterning defects. On the other hand, pepper plants with CaFFNsilencing flowered early. Therefore, the CaFFNgene acts as a flowering repressor in pepper. CaFFN may function as a transcriptional activator to activate the expression of CaAGL15and miR156eand as a transcriptional repressor to repress the expression of CaAG, CaAP1, CaSEP3, CaSOC1, and miR172bbased on a qRT-PCR assay. Direct activation of CaAGL15by CaFFN was detected using yeast one-hybrid and dual-luciferase reporter assays, consistent with the hypothesis that CaFFN regulates flowering time. Moreover, the CaFFNgene association analysis revealed a significant association with flowering time in a natural pepper population, indicating that the CaFFNgene has a broad effect on flowering time in pepper. Finally, the phylogeny, evolutionary expansion and expression patterns of CaFFN/AP2homologs were analyzed to provide valuable insight into CaFFN. This study increases our understanding of the involvement of CaFFNin controlling flowering time in pepper, thus making CaFFNa target gene for breeding early maturing pepper. |
