Graduate School of Agricultural Science, Kobe University, Kobe, Japan.
Plant Signal Behav. 2011 Oct;6(10):1431-3. doi: 10.4161/psb.6.10.17065. Epub 2011 Oct 1.
Hybrid necrosis sometimes appears in triploid hybrids between tetraploid wheat and Aegilops tauschii Coss. Two types of hybrid necrosis (type II and type III) were observed when cultivar Langdon was used as female parent for hybrid production. Type II necrosis symptoms occurred only under low temperature conditions, whereas bushy and dwarf phenotypes were observed under normal temperature conditions. The developmental plasticity might be related to a temperature-responsive alteration of meristematic activity at the crown tissue of triploid hybrids. Epistatic interaction between the AB and D genomes induced not only upregulation of a number of defense-related genes, but also extensive changes in plant architecture in the type II necrosis hybrids. Such phenotypic plasticity was also observed in other cross combinations between cultivated tetraploid wheat and type II necrosis-induced Ae. tauschii accessions. Wild tetraploid wheat, Triticum turgidum subspecies dicoccoides, did not induce type II necrosis in the triploid hybrids, indicating the possibility of identifying the chromosomal location of a causal gene for type II necrosis in the AB genome.
杂种细胞坏死有时出现在四倍体小麦与节节麦的三倍体杂种中。当使用朗登品种作为雌性亲本进行杂种生产时，观察到两种类型的杂种细胞坏死（II 型和 III 型）。只有在低温条件下才会出现 II 型坏死症状，而在正常温度条件下则会观察到丛生和矮化表型。发育可塑性可能与三倍体杂种冠组织分生组织活性的温度响应改变有关。AB 和 D 基因组之间的上位性相互作用不仅诱导了许多防御相关基因的上调表达，还导致 II 型坏死杂种的植物结构发生广泛变化。在栽培四倍体小麦与 II 型坏死诱导的节节麦品系之间的其他杂交组合中也观察到了这种表型可塑性。野生四倍体小麦，Triticum turgidum 亚种 dicoccoides，不会在三倍体杂种中诱导 II 型坏死，这表明有可能鉴定出 AB 基因组中导致 II 型坏死的基因的染色体位置。
