Behling William, Coombs Joseph, Ranaweera Thilanka, Vaillancourt Brieanne, Hamilton John P, Brose Julia, Buell C Robin, Douches David S
Department of Plant Soil and Microbial Sciences, Molecular Plant Science, Michigan State University, 1066 Bogue Street Room 2210, East Lansing, Michigan, 48824, USA.
Department of Plant Biology, Plant Biology Laboratories, Michigan State University, 612 Wilson Rd Room 166, East Lansing, Michigan, 48824, USA.
Plant J. 2025 Aug;123(4):e70426. doi: 10.1111/tpj.70426.
Solanum verrucosum Schlechtendal (2x = 2n = 24) is unique among the clade 4 Solanum Sect Petota species. In addition to being one of the only fully self-compatible diploid potato species, S. verrucosum is the only clade 4 species that lacks prezygotic interspecific reproductive barriers. This allows S. verrucosum to accept pollen from a broad range of Solanum species and thereby serving as a genetic "bridge" between the cultivated or primary potato gene pool and distantly related wild relatives in the tertiary gene pool. The genetic mechanisms underlying self-compatibility in Solanum often underpin interspecific compatibility interactions, which in S. verrucosum, has been attributed to the lack of S-RNase expression. Using an interspecific F2 mapping population (n = 150), we investigated the genetic mechanisms responsible for the lack of interspecific reproductive barriers in S. verrucosum. This F2 population was evaluated for the ability to accept pollen from two clade 1, 1 EBN species (S. pinnatisectum and S. tarnii); from which two QTL for interspecific compatibility were identified on chromosomes 1 and 11, explaining 56.6% of the phenotypic variation observed. To identify the genetic basis of interspecific compatibility, we generated a chromosome-scale genome assembly of S. verrucosum MSII1813-2 and performed gene expression profiling of reproductive organs. Differential gene expression of S-RNase, located within the chromosome 1 QTL, confirmed the central role of the S-locus and specifically, S-RNase, in interspecific compatibility. Discovery of a non-S-locus QTL is consistent with previous findings that other non-S-locus factors are necessary for interspecific compatibility in S. verrucosum.
疣柄茄（Solanum verrucosum Schlechtendal，2x = 2n = 24）在茄属马铃薯组第4进化枝物种中独具特色。除了是仅有的完全自交亲和的二倍体马铃薯物种之一外，疣柄茄还是第4进化枝中唯一缺乏合子前种间生殖障碍的物种。这使得疣柄茄能够接受多种茄属物种的花粉，从而在栽培马铃薯或初级马铃薯基因库与三级基因库中亲缘关系较远的野生近缘种之间充当遗传“桥梁”。茄属植物中自交亲和的遗传机制通常是种间亲和相互作用的基础，在疣柄茄中，这归因于缺乏S-RNase表达。我们利用一个种间F2作图群体（n = 150），研究了疣柄茄缺乏种间生殖障碍的遗传机制。对这个F2群体接受来自两个第1进化枝、1EBN物种（羽状裂茄和塔尼茄）花粉的能力进行了评估；从中在第1和第11号染色体上鉴定出两个种间亲和的QTL，解释了所观察到的56.6%的表型变异。为了确定种间亲和的遗传基础，我们构建了疣柄茄MSII1813-2的染色体水平基因组组装，并对生殖器官进行了基因表达谱分析。位于第1号染色体QTL内的S-RNase的差异基因表达，证实了S位点尤其是S-RNase在种间亲和中的核心作用。一个非S位点QTL的发现与之前的研究结果一致，即其他非S位点因子对于疣柄茄的种间亲和是必需的。
