Insights into the evolution of self-compatibility in Lycopersicon from a study of stylar factors
Insights into the evolution of self-compatibility in Lycopersicon from a study of stylar factors
复制标题
DOI：
10.1046/j.1365-313x.2002.01275.x
复制
发表时间：
2002-04-01
期刊：
影响因子：
7.2
通讯作者：
Kowyama, Y
中科院分区：
文献类型：
--
作者：
Kondo, K;Yamamoto, M;Kowyama, Y
为了阐明番茄自交不亲和性丧失的分子基础，对7个自交亲和（SC）和3个自交不亲和（SI）类群的S-RNase和HT-蛋白进行了分析。没有或低花柱RNA酶活性是一个共同的特点，在大多数SC类群检查，在所有SI物种中发现的活动的统一高水平。S-RNase基因很可能在四个红果SC分类群中缺失（L. esculentum，L.番茄变种cerasiforme，L. pimpinellifolium和L. cheesmanii），因为S-RNase基因不能从基因组DNA扩增。然而，S-RNase基因可以从三个绿色果实SC类群的基因组中扩增。L. chmielewskii和L.多毛草f. glabratum显示转录物积累减少，可能反映了S-RNase基因5'侧翼区的变化。其余的绿果SC种，L。parviflorum在其基因组中具有功能性S-RNase基因，该基因在花柱中以高水平表达，这表明导致低S-RNase活性的遗传因素。总之，这些结果表明，在番茄多样化的过程中，S-RNase基因发生了几个独立的突变，S-RNase功能的丧失不太可能是自交不亲和性丧失的主要原因。我们还研究了在自交不亲和性中起作用的HT-B基因。HT-B成绩单显着减少，在所有的SC类群检查的风格。描述了一种情况下，突变导致减少转录的HT-B在祖先SI物种是中央的番茄自交不亲和性的损失。
To elucidate the molecular basis of loss of self-incompatibility in Lycopersicon , S-RNases and HT-proteins were analysed in seven self-compatible (SC) and three self-incompatible (SI) taxa. No or low stylar RNase activity was a common feature in most SC taxa examined, in contrast to the uniformly high levels of activity found in all SI species. The S-RNase gene is most likely deleted in the four red-fruited SC taxa (L. esculentum, L. esculentum var. cerasiforme, L. pimpinellifolium and L. cheesmanii ) because S-RNase genes could not be amplified from genomic DNA. S-RNase genes could, however, be amplified from the genomes of the three green-fruited SC taxa examined. L. chmielewskii and L. hirsutum f. glabratum show a decreased accumulation of transcripts, possibly reflecting changes in the 5' flanking regions of the S-RNase genes. The remaining green-fruited SC species, L. parviflorum , has a functional S-RNase gene in its genome that is expressed at high levels in the style, suggesting a genetic factor responsible for the low S-RNase activity. Together these results argue for several independent mutations in the S-RNase gene over the course of Lycopersicon diversification, and that loss of S-RNase function is unlikely to the primary cause of the loss of self-incompatibility. We also examined the HT-B genes that play a role in self-incompatibility. HT-B transcripts were markedly reduced in the styles of all the SC taxa examined. A scenario is described where a mutation causing reduced transcription of HT-B in an ancestral SI species was central to the loss of self-incompatibility in Lycopersicon.