Functional analysis of genes for tyrosine catabolism that may be involved in annual and perennial differentiation of rice

谷胱甘肽S-转移酶（GSTs）是参与细胞内过氧化物质解毒的酶家族，而GSTZ是马来酰乙酰乙酸异构酶（MAAI），可使酪氨酸和苯丙氨酸分解途径的中间产物尿黑酸解毒。水稻基因组中含有两个拷贝的GSTZ基因。O. OsGSTZ 1和OsGSTZ 2的基因组DNA呈串联排列。上游OsGSTZ 1基因组成型表达，而下游OsGSTZ 2基因受胁迫诱导。我们分析了GSTZ基因在非洲栽培种O. glaberrima和野生种O. longistaminata的RT-PCR。结果表明，GSTZ 1和GSTZ 2基因在O. longistaminata中检测到GSTZ 2下游的cDNA片段，而在0. glaberrima。因此，获得了O.采用PCR基因组步移法检测光裂病。对O. sativa和野生稻O. glaberrima中OsGSTZ 1基因的第8内含子上游的基因组序列与一个BAC克隆高度同源，且方向相反，与O. sativa.这一结果表明OgGSTZ 1基因被破坏的巨大重排或倒位。这种遗传变异与O. glaberrima及其祖先野生种O.巴尔蒂。OgGSTZ 1基因在O. glaberrima主要在O. sativa和O. sativa和O. glaberrima，种子产量和一年生/多年生生境可能与氮代谢产物从叶片到种子的转运有关。将GSTZ 1基因导入O. glaberrima将一年生转变为多年生栖息地。

Although glutathione S-transferases (GSTs) are family of enzyme involved in the detoxification of per-oxidized materials in cells, Zeta class of GST (GSTZ) is reported as the maleylacetoacetate isomerase (MAAI) which detoxify homogentisate, intermediate in the catabolic pathway of tyrosine and phenylalanine. The genome of rice contains two copies of gene encoding GSTZ. Two GSTZ genes of O. sativa, OsGSTZ1 and OsGSTZ2, lies in tandem-arranged orientation. Upstream OsGSTZ1 gene constitutively expresses whereas downstream OsGSTZ2 gene is inducible by stresses. We analyzed the expression of GSTZ gene in African cultivated species O. glaberrima and wild species O. longistaminata by using RT-PCR. The result showed that both GSTZ1 and GSTZ2 genes expressed in O. longistaminata, whereas only cDNA fragment of downstream GSTZ2 was detected in 0. glaberrima. Thus, the genomic sequence of GSTZ1 locus of O. glaberrima was determined by PCR genomic walking. The sequence comparison between O. sativa and O. glaberrima revealed that genomic sequence upstream from the eighth intron of OgGSTZ1 gene was highly homologous, in inverted orientation, to a BAC clone, apart over 1-Mb from OsGSTZ1 gene in O. sativa. This result suggested that OgGSTZ1 gene was disrupted by huge rearrangement or inversion. The genetic alteration was shared with several lines of O. glaberrima and its ancestral wild species O. barthii. The lost of OgGSTZ1 gene in O. glaberrima is interesting which is mainly expressed 12-fold higher than OsGSTZ2 in O. sativa and some different characters exist between O. sativa and O. glaberrima, like seed yield and annual/perennial habitat that might be related with the translocation of nitrogen metabolites from leaves to seeds. GSTZ1 gene is being introduced into O. glaberrima to convert annual to perennial habitat.