Soybean Cyst Nematode Resistance Emerged via Artificial Selection of Duplicated Serine Hydroxymethyltransferase Genes.
Soybean Cyst Nematode Resistance Emerged via Artificial Selection of Duplicated Serine Hydroxymethyltransferase Genes.
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通过重复丝氨酸羟甲基转移酶基因的人工选择产生大豆胞囊线虫抗性
DOI：
10.3389/fpls.2016.00998
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发表时间：
2016
影响因子：
5.6
通讯作者：
Wang B
中科院分区：
文献类型：
--
作者：
Wu XY;Zhou GC;Chen YX;Wu P;Liu LW;Ma FF;Wu M;Liu CC;Zeng YJ;Chu AE;Hang YY;Chen JQ;Wang B
Rhg4是一个控制大豆胞囊线虫（SCN）抗性的主要大豆（Forrest栽培品种）数量性状基因座（QTL），其编码丝氨酸羟甲基转移酶（SHMT）。与敏感等位基因rhg4相比，耐药等位基因具有两个关键错义突变（P130 R和N358 Y）。为了了解该基因的进化历史，利用来自18种代表性植物的117个SHMT家族成员的序列重建了它们的进化史。根据这一系统发育，植物SHMT基因家族可分为两大类和四个亚类（Ia、Ib、IIa和IIb）。rhg4基因属于Ia亚群谱系，是从大豆属物种中最近的一次重复事件进化而来的。为了进一步探索SCN抗性等位基因是如何出现的，我们从33个栽培大豆品种和68个野生大豆品种中分离了rhg4基因及其最接近的同源物rhg4h基因。结果表明，基因重复后，大豆rhg4基因积累了更多的非同义突变比rhg4h。虽然在野生大豆中检测到更多的分离位点和基因单倍型，但在野生大豆中未发现抗SCN的Rhg4等位基因（以单倍型4为代表）。相反，在野生大豆中观察到一个非常相似的等位基因，单倍型3，频率为7.4%，尽管它缺乏两个关键的非同义替换。总之，这些发现支持SCN抗性Rhg4等位基因可能是在大豆驯化过程中通过人工选择出现的，基于从野生大豆遗传的SCN敏感等位基因。
A major soybean (Forrest cultivar) quantitative trait locus (QTL) gene, Rhg4, which controls resistance to soybean cyst nematodes (SCN), encodes the enzyme serine hydroxylmethyltransferase (SHMT). The resistant allele possesses two critical missense mutations (P130R and N358Y) compared to that of the sensitive allele, rhg4. To understand the evolutionary history of this gene, sequences of 117 SHMT family members from 18 representative plant species were used to reconstruct their phylogeny. According to this phylogeny, the plant SHMT gene family can be divided into two groups and four subgroups (Ia, Ib, IIa, and IIb). Belonging to the Subgroup Ia lineage, the rhg4 gene evolved from a recent duplication event in Glycine sp.. To further explore how the SCN-resistant allele emerged, both the rhg4 gene and its closest homolog, the rhg4h gene, were isolated from 33 cultivated and 68 wild soybean varieties. The results suggested that after gene duplication, the soybean rhg4 gene accumulated a higher number of non-synonymous mutations than rhg4h. Although a higher number of segregating sites and gene haplotypes were detected in wild soybeans than in cultivars, the SCN-resistant Rhg4 allele (represented by haplotype 4) was not found in wild varieties. Instead, a very similar allele, haplotype 3, was observed in wild soybeans at a frequency of 7.4%, although it lacked the two critical non-synonymous substitutions. Taken together, these findings support that the SCN-resistant Rhg4 allele likely emerged via artificial selection during the soybean domestication process, based on a SCN-sensitive allele inherited from wild soybeans.