有些植物需要藉由媒介來傳遞花粉,，但有些則可利用自花受粉（self-pollinate）的方式，達到交配的目的,。試想某天,，若沒有傳遞花粉的媒介，想必只有那些能自花受粉的植物得以存活,。June Nasrallah教授表示：「此研究長期的目標是要了解為何自花受粉的情況無法發(fā)生在“自我不親合性”（self-incompatibility）的植物中,，而PUB8基因的發(fā)現(xiàn)也許能作為一個批注?！勾搜芯堪l(fā)表于5月1日的Current Biology期刊,。
長期以來Nasrallah的研究團隊都以阿拉伯芥（Arabidopsis thaliana）作為研究模式，這種植物廣泛的被用于遺傳研究,，研究人員先前已發(fā)現(xiàn)SCR及SRK基因是導(dǎo)致植物「自我不親合性」的關(guān)鍵基因,。其中SCR轉(zhuǎn)譯出的蛋白質(zhì)會在花粉粒表面，而SRK表現(xiàn)的蛋白則為柱頭細胞細胞膜表面的接受器,，當這兩個蛋白位于同一株植物,，柱頭就會排斥花粉,，無法達到受粉的結(jié)果,。
阿拉伯芥具有很高的自我繁殖力,，但研究人員將SCR和SRK基因置入時，便產(chǎn)生了假性自花受粉的現(xiàn)象（pseudo self-compatible）,，也就是當花粉無法從其它植物而來時,，才會進行自花受粉。Nasrallah教授表示：「這是植物交配非常好的策略,，因為幾乎不需要傳媒就可以受粉,。」而另一位研究人員Pei Liu也發(fā)現(xiàn),，基因組中的PUB8基因很可能可以調(diào)控SRK的表現(xiàn),，因為PUB8基因的變異與假性自花受粉的現(xiàn)象有很大的關(guān)聯(lián)性，在演化的角度上PUB8基因可能是調(diào)控假性自花受粉到植物「自我不親合性」（self-incompatibility）的關(guān)鍵基因,。
（編譯/陳瑞娟） (資料來源 : Bio.com)
英文原文鏈接：
http://news.biocompare.com/newsstory.asp?id=180440
原始出處:
Current Biology, Vol 17, 734-740, 17 April 2007
Report
A Cryptic Modifier Causing Transient Self-Incompatibility in Arabidopsis thaliana
Pei Liu,1 Susan Sherman-Broyles,1 Mikhail E. Nasrallah,1 and June B. Nasrallah1,
1 Department of Plant Biology, Cornell University, Ithaca, New York 14853
Corresponding author
June B. Nasrallah
[email protected]
Breakdown of the pollination barrier of self-incompatibility (SI) in older flowers, a phenomenon known as pseudo-self-compatibility or transient SI, has been described as an advantageous reproductive assurance strategy that allows selfing after opportunities for out-crossing have been exhausted [1, 2, 3, 4, 5, 6, 7, 8, 9]. Pseudo-self-compatibility is quite prevalent as a mixed mating strategy in nature, but the underlying molecular mechanisms are not known. We had previously shown that Arabidopsis thaliana exhibits cryptic natural variation for pseudo-self-compatibility, which is uncovered by transformation of different accessions with SI specificity-determining SRK and SCR genes from its self-incompatible sister species A. lyrata[10, 11]. Here, by using this transgenic A. thaliana model, we show that pseudo-self-compatibility is caused by a hypomorphic allele of PUB8, an S-locus-linked gene encoding a previously uncharacterized ARM repeat- and U box-containing protein that regulates SRK transcript levels. This is the first gene underlying pseudo-self-compatibility to be identified and the first report in which cryptic natural variation unveiled by a transgene enabled the cloning of a gene for a complex trait.
