Current Biology：能操控植物自花授粉的基因
有些植物需要藉由媒介来传递花粉，但有些则可利用自花受粉（self-pollinate）的方式，达到交配的目的。试想某天，若没有传递花粉的媒介，想必只有那些能自花受粉的植物得以存活。June Nasrallah教授表示：「此研究长期的目标是要了解为何自花受粉的情况无法发生在“自我不亲合性”（self-incompatibility）的植物中，而PUB8基因的发现也许能作为一个批注。」此研究发表于5月1日的Current Biology期刊。
长期以来Nasrallah的研究团队都以阿拉伯芥（Arabidopsis thaliana）作为研究模式，这种植物广泛的被用于遗传研究，研究人员先前已发现SCR及SRK基因是导致植物「自我不亲合性」的关键基因。其中SCR转译出的蛋白质会在花粉粒表面，而SRK表现的蛋白则为柱头细胞细胞膜表面的接受器，当这两个蛋白位于同一株植物，柱头就会排斥花粉，无法达到受粉的结果。
阿拉伯芥具有很高的自我繁殖力，但研究人员将SCR和SRK基因置入时，便产生了假性自花受粉的现象（pseudo self-compatible），也就是当花粉无法从其它植物而来时，才会进行自花受粉。Nasrallah教授表示：「这是植物交配非常好的策略，因为几乎不需要传媒就可以受粉。」而另一位研究人员Pei Liu也发现，基因组中的PUB8基因很可能可以调控SRK的表现，因为PUB8基因的变异与假性自花受粉的现象有很大的关联性，在演化的角度上PUB8基因可能是调控假性自花受粉到植物「自我不亲合性」（self-incompatibility）的关键基因。
（编译/陈瑞娟） (资料来源 : Bio.com)
http://news.biocompare.com/newsstory.asp?id=180440
原始出处:
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
jbn2@cornell.edu
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.
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