Allelic Variation of Soybean Maturity Genes E1–E4 in the Huang-Huai-Hai River Valley and the Northwest China

Cailong Xu,Shi Sun,Xinyue Zhang,Tianfu Han,Wenwen Song,Tingting Wu,Cunxiang Wu,Huiwen Wen

doi:10.3390/agriculture11060478

Cailong Xu, Shi Sun + Show 6 more

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https://doi.org/10.3390/agriculture11060478

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Abstract

Soybean is planted in a wide span of the world, and flowering and maturity time is an important trait determining soybean yield formation and adaptation. Maturity loci E1, E2, E3 and E4 were frequently reported as the most influential genetic loci for soybean flowering and maturity. To understand the allelic variation and assess the phenological traits of cultivars with different E allelic combinations in natural environments, 251 cultivars of maturity group (MG) I–V were field tested in 42 locations across four sub-regions in the Huang-Huai-Hai and Northwest region of China and genotyped with KASP markers for E1–E4 loci. The results indicated that mutant alleles were only found in the E1 and E2 locus, all of the cultivars carried functional alleles in the E3 and E4 loci in this area, with the frequency of mutant allele to be higher in early maturity groups (MGs) than late MGs. Among nine E allelic combinations in this area, one photoperiodic insensitive mutation in E2 loci (E1/e2-ns/E3-Ha/E4 and E1/e2-ns/E3-Mi/E4) made up the largest proportion (25.10 and 18.33%), while two photoperiodic insensitive mutations in both E1 and E2 loci (e1-as/e2-ns/E3-Ha/E4) (1.20%) occupied the lowest proportion in this panel. The major combinations of E locus for MGI, MGII and MG III in this area were E1/E2-dl/E3-Mi/E4, E1/e2-ns/E3-Mi/E4 and E1/e2-ns/E3-Ha/E4, respectively. Cultivars carrying e1-as/e2-ns/E3-Ha/E4 genotype flowered earliest (34 days) on average, 7.6 days earlier than the latest-flowering E haplotype (E1/e2-ns/E3-Ha/E4). This study provided an opportunity to detect the E allelic combinations in the Huang-Huai-Hai River Valley and the Northwest China, which would facilitate the improvement of soybean adaptation in the future.

Highlights

Soybean was originated from the Southeastern Asia and expanded to the tropical and high latitude zones [1,2]
At the E2 locus, three allelic variations were found with the frequency of 28, 28 and 44% for E2-dl, E2-in and e2-ns alleles, respectively
A total of nine allelic combinations of these four E genes were identified across 251 cultivars

Summary

Introduction

Soybean was originated from the Southeastern Asia and expanded to the tropical and high latitude zones [1,2]. Flowering time and maturity are the key traits determining the adaptation zone of soybean varieties. Soybean cultivars with different photo-thermal sensitivity adapt to different geographic zones [3]. Cultivars carrying dominant alleles of E1, E2, E3, E4 genes showed a delay in flowering and maturity. Allelic variations in each of E1, E2, E3, E4 loci were identified to have different functions on flowering and maturity. E2-ns, an SNP caused a nonsense mutation, is non-functional [12]. Both E3 and E4 are phytochrome A genes. E4 (SORE-1), a retrotransposon caused truncated protein with 237 amino acids, and e4-oto, e4-tsu, e4-kam and e4-kes, single base-pair deletions caused truncated proteins with different length, respectively, are non-functional [14] E3-Mi and E3-Ha are functional, while e3-ns, e3-tr, e3-fs and e3-Mo are nonfunctional [13,15]. e4 (SORE-1), a retrotransposon caused truncated protein with 237 amino acids, and e4-oto, e4-tsu, e4-kam and e4-kes, single base-pair deletions caused truncated proteins with different length, respectively, are non-functional [14]

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