Search

Genetic adaptation of soybean phenological stages to high‐latitude long‐day environments is the major pre‐requisite for enhancing regional plant‐based protein production. Both E‐genes controlling flowering and growing environment determine timing of flowering and maturity, and E‐gene composition might differ between Chinese and European soybeans bearing the potential for improving adaptability. Therefore, 140 early maturity elite soybean cultivars of either Chinese or European origin were genotyped for the E1 to E4 flowering loci, and genotypes were tested across 17 European environments spanning a latitude range from 45 to 52°N in order to determine effects of various E‐allele combinations. Differences in E‐allele composition between Chinese and European cultivars were largest for the loci E1 and E3. Wild‐type alleles significantly delayed flowering, and effects of particular E‐alleles were depending on geographic latitude. Consequently, photoperiod‐insensitive E‐haplotypes carrying several non‐functional alleles proved to be suitable for cultivation in higher latitudes, whereas photoperiod‐sensitive late‐maturity E‐haplotypes are adapted to lower latitudes only. Thus, breeding for new E‐haplotypes through combining Chinese and European alleles could enhance the potential for further soybean adaptation to northern growing regions. [ABSTRACT FROM AUTHOR]

Summary: Soybean is a short‐day plant that typically flowers earlier when exposed to short‐day conditions. However, the identification of genes associated with earlier flowering time but without a yield penalty is rare. In this study, we conducted genome‐wide association studies (GWAS) using two re‐sequencing datasets that included 113 wild soybeans (G. soja) and 1192 cultivated soybeans (G. max), respectively, and simultaneously identified a candidate flowering gene, qFT13‐3, which encodes a protein homologous to the pseudo‐response regulator (PRR) transcription factor. We identified four major haplotypes of qFT13‐3 in the natural population, with haplotype H4 (qFT13‐3H4) being lost during domestication, while qFT13‐3H1 underwent natural and artificial selection, increasing in proportion from 4.5% in G. soja to 43.8% in landrace and to 81.9% in improve cultivars. Notably, most cultivars harbouring qFT13‐3H1 were located in high‐latitude regions. Knockout of qFT13‐3 accelerated flowering and maturity time under long‐day conditions, indicating that qFT13‐3 functions as a flowering inhibitor. Our results also showed that qFT13‐3 directly downregulates the expression of GmELF3b‐2 which is a component of the circadian clock evening complex. Field trials revealed that the qft13‐3 mutants shorten the maturity period by 11 days without a concomitant penalty on yield. Collectively, qFT13‐3 can be utilized for the breeding of high‐yield cultivars with a short maturity time suitable for high latitudes. [ABSTRACT FROM AUTHOR]

The yield of soybean is positively correlated with the duration of reproductive growth, which delays the aging of leaves after flowering, enhances their physiological performance, and supports growing plants with heavier grains. Leaf yellowing is one of the distinctive features of plant aging. Studies on leaf yellowing at the late stage of soybean drum grain have rarely been reported. The early yellowing feature of soybean late tympanic leaves was controlled by a single recessive nuclear gene, according to the genetic analysis of the hybrid of the early yellowing mutant ly and wild-type ofc in this study. Using Molecular Marker to Map-Based Cloning, a 2.23 Mb preliminary localization interval on chromosome 19 was obtained. The interval was shortened to 1.75 Mb and contained 219 genes. When this interval was combined with RNA-Seq analysis, 12 candidate genes were detected, including 4 SNP variant genes and 8 differentially expressed genes. The findings of this study provides the framework for the cloning of genes that cause aging and yellowing during the filling later period in soybean. [ABSTRACT FROM AUTHOR]

BACKGROUND: Artificial selection played an important role in the origin of modern Glycine max cultivars from the wild soybean Glycine soja. To elucidate the consequences of artificial selection accompanying the domestication and modern improvement of soybean, 25 new and 30 published whole-genome re-sequencing accessions, which represent wild, domesticated landrace, and Chinese elite soybean populations were analyzed. RESULTS: A total of 5,102,244 single nucleotide polymorphisms (SNPs) and 707,969 insertion/deletions were identified. Among the SNPs detected, 25.5% were not described previously. We found that artificial selection during domestication led to more pronounced reduction in the genetic diversity of soybean than the switch from landraces to elite cultivars. Only a small proportion (2.99%) of the whole genomic regions appear to be affected by artificial selection for preferred agricultural traits. The selection regions were not distributed randomly or uniformly throughout the genome. Instead, clusters of selection hotspots in certain genomic regions were observed. Moreover, a set of candidate genes (4.38% of the total annotated genes) significantly affected by selection underlying soybean domestication and genetic improvement were identified. CONCLUSIONS: Given the uniqueness of the soybean germplasm sequenced, this study drew a clear picture of human-mediated evolution of the soybean genomes. The genomic resources and information provided by this study would also facilitate the discovery of genes/loci underlying agronomically important traits.

Functional identification of salt-tolerant genes is crucial for the improvement of soybean varieties and the development and utilization of saline-alkali land. Under salt stress, crops reduce the effect of salt damage on crop yield by synthesizing and accumulating betaine as osmotic protective agent. BADH gene is been proved to regulate plant response to stress in many plants, but the regulation mechanism in soybean is not clear. In this study, GmBADH1 gene was cloned, and qRT-PCR showed that the gene was expressed stems and leaves, especially in roots. The expression vector constructed by CRISPR/Cas9 system was transferred into soybean variety JACK by Agrobacterium-mediated soybean genetic transformation technology, and three targeted mutations that could regulate the salt tolerance of soybean were produced. They all occurred in the coding region, which had three difference of deletion 19 bp, insertion 1 bp, and insertion 9 bp to replace 2 bp. The first two, premature termination codons, resulting in truncated BADH1 protein, the latter occurred frameshift mutation. The mutant homozygous plants were treated with salt at the emergence stage and seedling stage, respectively. The results showed that the salt tolerance of the mutant homozygous plants was significantly lower than that of the wild type at seedling stage, and there was no significant difference compared with the wild type at seeding stage, which indicating that GmBADH1 gene may mainly regulate the salt tolerance of seedling stage. This study provides a basis for further excavation of soybean salt-tolerant genes and cultivation of soybean salt-tolerant varieties. [ABSTRACT FROM AUTHOR]

Salinity greatly affects the production of soybeans in arid and semi-arid lands around the world. The responses of soybeans to salt stress at germination, emergence, and other seedling stages have been evaluated in multitudes of studies over the past decades. Considerable salt-tolerant accessions have been identified. The association between salt tolerance responses during early and later growth stages may not be as significant as expected. Genetic analysis has confirmed that salt tolerance is distinctly tied to specific soybean developmental stages. Our understanding of salt tolerance mechanisms in soybeans is increasing due to the identification of key salt tolerance genes. In this review, we focus on the methods of soybean salt tolerance screening, progress in forward genetics, potential mechanisms involved in salt tolerance, and the importance of translating laboratory findings into field experiments via marker-assisted pyramiding or genetic engineering approaches, and ultimately developing salt-tolerant soybean varieties that produce high and stable yields. Progress has been made in the past decades, and new technologies will help mine novel salt tolerance genes and translate the mechanism of salt tolerance into new varieties via effective routes. [ABSTRACT FROM AUTHOR]