Novel Genomic Regions of Fusarium Wilt Resistance in Bottle Gourd [Lagenaria siceraria (Mol.) Standl.] Discovered in Genome-Wide Association Study

Yanwei Li,Xinyi Wu,Baogen Wang,Ying Wang,Zhongfu Lu,Guojing Li,Jian Wang,Xiaohua Wu

doi:10.3389/fpls.2021.650157

Yanwei Li, Xinyi Wu + Show 6 more

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https://doi.org/10.3389/fpls.2021.650157

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Abstract

Fusarium wilt (FW) is a typical soil-borne disease that seriously affects the yield and fruit quality of bottle gourd. Thus, to improve resistance to FW in bottle gourd, the genetic mechanism underlying FW resistance needs to be explored. In this study, we performed a genome-wide association study (GWAS) based on 5,330 single-nucleotide polymorphisms (SNPs) and 89 bottle gourd accessions. The GWAS results revealed a total of 10 SNPs (P ≤ 0.01, −log10P ≥ 2.0) significantly associated with FW resistance that were detected in at least two environments (2019DI, 2020DI, and the average across the 2 years); these SNPs were located on chromosomes 1, 2, 3, 4, 8, and 9. Linkage disequilibrium (LD) block structure analysis predicted three potential candidate genes for FW resistance. Genes HG_GLEAN_10001030 and HG_GLEAN_10001042 were within the range of the mean LD block of the marker BGReSe_14202; gene HG_GLEAN_10011803 was 280 kb upstream of the marker BGReSe_00818. Real-time quantitative PCR (qRT-PCR) analysis showed that HG_GLEAN_10011803 was significantly up-regulated in FW-infected plants of YD-4, Yin-10, and Hanbi; HG_GLEAN_10001030 and HG_GLEAN_10001042 were specifically up-regulated in FW-infected plants of YD-4. Therefore, gene HG_GLEAN_10011803 is likely the major effect candidate gene for resistance against FW in bottle gourd. This work provides scientific evidence for the exploration of candidate gene and development of functional markers in FW-resistant bottle gourd breeding programs.

Highlights

Bottle gourd [Lagenaria siceraria (Mol.) Standl.] (2n = 2 × = 22), known as calabash or long melon, is a member of the Legendaria genus, Cucurbitaceous family, and is an annual plant (Whitaker, 1971; Erickson et al, 2005)
Since this pathogen can survive in the absence of host-infected plants, once the disease occurs in the field, F. oxysporum is likely to remain in the soil indefinitely, which seriously affects the yield of crops (Cha et al, 2016; Khan et al, 2017)
The pathogenicity results showed that bottle gourd plants had obvious wilt infection symptoms, featured by the first and second leaves that were more than 50% wilted and the third and fourth leaves that were crumpled

Summary

Introduction

Fusarium wilt (FW), which is caused by Fusarium oxysporum, is a typical soil-borne disease of economic crops worldwide (Katan, 1994; Wechter et al, 2012; Bodah, 2017). Since this pathogen can survive in the absence of host-infected plants, once the disease occurs in the field, F. oxysporum is likely to remain in the soil indefinitely, which seriously affects the yield of crops (Cha et al, 2016; Khan et al, 2017).

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