Identification of Fruit Traits Related QTLs and a Candidate Gene, CaBRX, Controlling Locule Number in Pepper (Capsicum annuum L.)

Xiao Ma,Zhen-Hui Gong,Yi-Ming Qiao,Ya-Nan Yu,Yang Li

doi:10.3390/horticulturae8020146

Xiao Ma, Zhen-Hui Gong + Show 3 more

Open Access

https://doi.org/10.3390/horticulturae8020146

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Journal: Horticulturae	Publication Date: Feb 9, 2022
Citations: 2	License type: CC BY 4.0

Affiliation: North West Agriculture and Forestry University

Abstract

Fruit traits are important in pepper (Capsicum annuum L.) and affect its quality and yield. These traits are controlled by quantitative trait loci (QTLs). In this study, we identified many major QTLs that control fruit length (Ftl), fruit diameter (Ftd), fruit shape (Fts), fruit weight (Ftw) and locule number (Lcn) in the F2 and F2:3 populations developed from the QTL mapping of GS6 (P1) and Qiemen (P2). A total of 111 simple sequence repeats and insertion/deletion markers were utilized to construct a linkage map with 12 linkage groups over a length of 1320.72 cM. An inclusive composite interval mapping analysis indicated that many QTLs were detected and included ftl2.1, ftd2.1, fts1.1, ftw2.1 and lcn1.1. As a novel QTL, lcn1.1 was located between HM1112 and EPMS709, and the genetic distance was 3.18 cM covering 60 predicted genes. Within the region, we identified Capana01g004285 as a candidate gene by functional annotation and expression analysis and found that it encodes the BREVIS RADIX (BRX) protein. Knockdown of CaBRX through the virus-induced gene silencing approach in GS6 reduced the number of locules and influenced the expressions of genes related to flower and locule development, suggesting that CaBRX plays an important function in the development of locules.

Highlights

Pepper (Capsicum spp.) is a member of the Solanaceae family and is a vital vegetable globally [1]
In the F2 and F2:3 populations, the fruit length (Ftl) is skewed toward Qiemen, while the fruit weight (Ftw), fruit diameter (Ftd) and locule number (Lcn) are skewed toward GS6
Correlation analyses were used to reveal the link between each other and showed that Lcn significantly positively correlated with Ftw

Summary

Introduction

Pepper (Capsicum spp.) is a member of the Solanaceae family and is a vital vegetable globally [1]. 31 species of Capsicum are recognized in the genus, and five have been domesticated. C. annuum is the oldest domesticated crop in the Americas and the most widely grown crop in the world [3]. Pepper fruits are widely used in the food and chemical industries owing to their unique pungency and rich nutrients [3]. The yield is the typical quantitative trait and is influenced by many factors, including fruit dimensions, the number of fruits, and fruit weight [5]. Recent advances in quantitative trait loci (QTLs) mapping have identified many genes that contribute to the control of traits in fruit, such as plant height, fruit weight, fruit shape and locule number in pepper [6,7]

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