Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
Plant Mol Biol. 2012 Sep;80(2):131-55. doi: 10.1007/s11103-012-9932-z. Epub 2012 Jun 12.
Transcriptional mapping experiments of the major soybean cyst nematode resistance locus, rhg1, identified expression of the vesicular transport machinery component, α soluble NSF attachment protein (α-SNAP), occurring during defense. Sequencing the α-SNAP coding regions from the resistant genotypes G. max ([Peking/PI 548402]) and G. max ([PI 437654]) revealed they are identical, but differ from the susceptible G. max ([Williams 82/PI 518671]) by the presence of several single nucleotide polymorphisms. Using G. max ([Williams 82/PI 518671]) as a reference, a G → T(2,822) transversion in the genomic DNA sequence at a functional splice site of the α-SNAP([Peking/PI 548402]) allele produced an additional 17 nucleotides of mRNA sequence that contains an in-frame stop codon caused by a downstream G → A(2,832) transition. The G. max ([Peking/PI 548402]) genotype has cell wall appositions (CWAs), structures identified as forming as part of a defense response by the activity of the vesicular transport machinery. In contrast, the 17 nt α-SNAP([Peking/PI 548402]) mRNA motif is not found in G. max ([PI 88788]) that exhibits defense to H. glycines, but lack CWAs. The α-SNAP([PI 88788]) promoter contains sequence elements that are nearly identical to the α-SNAP([Peking/PI 548402]) allele, but differs from the G. max ([Williams 82/PI 518671]) ortholog. Overexpressing the α-SNAP([Peking/PI 548402]) allele in the susceptible G. max ([Williams 82/PI 518671]) genotype suppressed H. glycines infection. The experiments indicate a role for the vesicular transport machinery during infection of soybean by the soybean cyst nematode. However, increased GmEREBP1, PR1, PR2, PR5 gene activity but suppressed PR3 expression accompanied the overexpression of the α-SNAP([Peking/PI 548402]) allele prior to infection.
大豆胞囊线虫主要抗性基因 rhg1 的转录图谱实验鉴定了囊泡运输机制成分 α 可溶性 NSF 附着蛋白 (α-SNAP) 的表达，该蛋白在防御过程中发生。对来自抗源基因型 G. max ([Peking/PI 548402]) 和 G. max ([PI 437654]) 的 α-SNAP 编码区进行测序，结果表明它们是相同的，但与易感基因型 G. max ([Williams 82/PI 518671]) 不同，后者存在几个单核苷酸多态性。使用 G. max ([Williams 82/PI 518671]) 作为参考，在 α-SNAP([Peking/PI 548402]) 等位基因的功能性剪接位点的基因组 DNA 序列中，G→T(2,822)颠换产生了额外的 17 个 mRNA 序列核苷酸，其中包含一个由下游 G→A(2,832) 转换引起的框内终止密码子。G. max ([Peking/PI 548402]) 基因型具有细胞壁附着物 (CWA)，这些结构被鉴定为通过囊泡运输机制的活性形成防御反应的一部分。相比之下，在表现出对 H. glycines 抗性但缺乏 CWA 的 G. max ([PI 88788]) 中，没有发现 17 nt α-SNAP([Peking/PI 548402]) mRNA 基序。α-SNAP([PI 88788]) 启动子包含与 α-SNAP([Peking/PI 548402]) 等位基因几乎相同的序列元件，但与 G. max ([Williams 82/PI 518671]) 同源物不同。在易感基因型 G. max ([Williams 82/PI 518671]) 中过表达 α-SNAP([Peking/PI 548402]) 等位基因可抑制 H. glycines 感染。实验表明，在大豆胞囊线虫感染大豆的过程中，囊泡运输机制发挥了作用。然而，在感染前过表达 α-SNAP([Peking/PI 548402]) 等位基因时，GmEREBP1、PR1、PR2、PR5 基因的活性增加，但 PR3 表达受到抑制。
