Pepper Fruit Elongation Is Controlled by Capsicum annuum Ovate Family Protein 20

Abstract

Fruit shape is one of the most important quality traits of pepper (Capsicum spp.) and is used as a major attribute for the classification of fruit types. Wide natural variation in fruit shape exists among the major cultivated species Capsicum annuum, allowing the identification of several QTLs controlling the trait. However, to date, no genes underlying fruit shape QTLs have been conclusively identified, nor has their function been verified in pepper. We constructed a mapping population from a cross of round- and elongated-fruited C. annuum parents and identified a single major QTL on chromosome 10, termed fs10, explaining 68 and 70% of the phenotypic variation for fruit shape index and for distal fruit end angle, respectively. The QTL was mapped in several generations and was localized to a 5 Mbp region containing the ortholog of SlOFP20 that suppresses fruit elongation in tomato. Virus-induced gene silencing of the pepper ortholog CaOFP20 resulted in increased fruit elongation on two independent backgrounds. Furthermore, CaOFP20 exhibited differential expression in fs10 near-isogenic lines, as well as in an association panel of elongated- and round-fruited accessions. A 42-bp deletion in the upstream region of CaOFP20 was most strongly associated with fruit shape variation within the locus. Histological observations in ovaries and fruit pericarps indicated that fs10 exerts its effect on fruit elongation by controlling cell expansion and replication. Our results indicate that CaOFP20 functions as a suppressor of fruit elongation in C. annuum and is the most likely candidate gene underlying fs10.

Multi‐environment association study highlights candidate genes for robust agronomic quantitative trait loci in a novel worldwide Capsicum core collection

“…The OVATE homolog positioned at 155 Mb on chromosome P2, is closely linked to the fruit weight QTL fw2.1 (Zygier et al., 2005; Table S1) and close to the QTL FWe‐P2.4 , detected with the strongest marker‐FWe association at position 160 Mb. Moreover, C. annuum OVATE FAMILY PROTEIN 20 ( CaOFP20 ), known to control fruit elongation through cell expansion and replication (Borovsky et al., 2022), is 1.2 Mb distant from our strongest associations for FLe, FShI, PTh, and FF ( FLe‐P10.1 , FShI‐P10.1 , PTh‐P10.1 , and FF‐P10.1 ) and one of our strongest associations for FShO ( FShO‐P10.1 ), which are all colocalized on chromosome P10. In peach, a chromosomal inversion downstream of an OFP gene is responsible for the flat fruit shape, comparable to the oblate pepper phenotype (Zhou et al., 2021).…”

Identification of CaPCR1, an OFP gene involved in pointed vs. concave fruit tip regulation in pepper (Capsicum annuum L.) using recombinant inbred lines

“…In pepper, the downregulation of CaOvate changed the fruit from round to oblong, indicating that CaOvate was indeed involved in determining fruit shape (Tsaballa et al 2011). Virus-induced gene silencing of CaOFP20 also led to increased fruit length, indicating that CaOPF20 functions as a suppressor of fruit elongation in pepper (Borovsky et al 2022). However, genes in the OFP family that directly regulate fruit tip shape were not found.…”

A combinatorial TRM‐OFP module bilaterally fine‐tunes tomato fruit shape

“…Natural variation in cultivated tomato led to the map‐based cloning of these genes (Liu et al ., 2002; Wu et al ., 2018). In addition, other OFP members, such as CaOFP20 in pepper (Borovsky et al ., 2021), OFP1 , 2 , 3 , 5 in Arabidopsis (Wang et al ., 2007, 2011; Zhang et al ., 2020), OFP2 , 8 , 19 in rice (Schmitz et al ., 2015; Yang et al ., 2016, 2018; Zhao et al ., 2018), OFP13 in melon, and OFP20 in potato (Wu et al ., 2018), have also been implicated or demonstrated to regulate organ shape in the respective species. Ovate Family Proteins are proposed to change cell division patterns by controlling the plane of cell division as well as cell expansion (Wang et al ., 2011; Wu et al ., 2018; Yang et al ., 2018; Snouffer et al ., 2020).…”