Cloning and characterization of homeologous cellulose synthase catalytic subunit 2 genes from allotetraploid cotton (Gossypium hirsutum L.)
Cloning and characterization of homeologous cellulose synthase catalytic subunit 2 genes from allotetraploid cotton (Gossypium hirsutum L.)
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DOI：
10.1016/j.gene.2011.12.018
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发表时间：
2012-02-25
期刊：
影响因子：
3.5
通讯作者：
Fang, David D.
中科院分区：
文献类型：
--
作者：
Kim, Hee Jin;Triplett, Barbara A.;Fang, David D.
纤维素合成酶催化亚基(CEAs)是植物体内纤维素生物合成的多亚基复合体中的催化部位。CEAS在二倍体植物中已经得到了广泛的研究，但在多倍体植物中的特性还不是很好。陆地棉是一种异源四倍体棉种，产量占世界棉纤维的90%以上。虽然陆地棉CesA(GhCesA)负责棉纤维中纤维素的产生，但GhCesA基因的数量非常有限。在这里，我们报道了从异源四倍体棉花中分离和鉴定了一对同源的CesA2基因及其全长cDNA。从陆地棉BAC文库中筛选出A亚基因组中的GhCesA2-A(T)基因和D亚基因组中的GhCesA2-D-T基因。这些基因在整个序列中有92%的序列相似性。GhCesA2-A(T)(1,039个氨基酸)和GhCesA2-D-T(1,040个氨基酸)推导的氨基酸序列除4个氨基酸外，其余氨基酸序列基本一致，而非编码序列则有差异。序列分析表明，GhCesA2-A(T)的所有外显子都含有一致剪接供体二核苷酸，但GhCesA2-D-T的一个外显子含有非一致剪接供体二核苷酸。尽管非共识剪接供体二核苷酸先前被认为参与了选择性剪接或假原化，但我们的结果表明，大多数GhCesA2-A(T)和GhCesA2-DT转录本由功能转录本和全长转录本组成，很少有证据表明在棉纤维发育中存在替代的mRNA异构体。表达分析表明，GhCesA2-A(T)和GhCesA2-D-T具有共同的时空表达模式，它们在棉纤维发育过程中的纤维素生物合成阶段高度优先表达。GhCesA2-A(T)和GhCesA2-D-T在一个纤维束强度较高的近等基因系(NIL)的发育纤维中的表达水平高于另一个纤维束强度较低的近等基因系(NIL)，这表明与次生细胞壁纤维素生物合成相关的基因在发育过程中的差异表达可能影响棉花纤维的特性。爱思唯尔出版公司(Elsevier B.V.)
Cellulose synthase catalytic subunits (CesAs) are the catalytic sites within a multisubunit complex for cellulose biosynthesis in plants. CesAs have been extensively studied in diploid plants, but are not well characterized in polyploid plants. Gossypium hirsutum is an allotetraploid cotton species producing over 90% of the world's cotton fibers. Although G. hirsutum CesAs (GhCesAs) are responsible for cellulose production in cotton fiber, very limited numbers of GhCesA genes have been identified. Here, we report isolating and characterizing a pair of homeologous CesA2 genes and their full-length cDNAs from allotetraploid cotton. The GhCesA2-A(T) gene from the A-subgenome and GhCesA2-D-T gene from the D-subgenome were screened from a G. hirsutum BAC library. These genes shared 92% sequence similarity throughout the entire sequence. The coding sequences were nearly identical, and the deduced amino acid sequences from GhCesA2-A(T) (1,039 amino acids) and GhCesA2-D-T (1,040 amino acids) were identical except four amino acids, whereas the noncoding sequences showed divergence. Sequence analyses showed that all exons of GhCesA2-A(T) contained consensus splice donor dinucleotides, but one exon in GhCesA2-D-T contained nonconsensus splice donor dinucleotides. Although the nonconsensus splice donor dinucleotides were previously suggested to be involved in alternative splice or pseudogenization, our results showed that a majority of GhCesA2-A(T) and GhCesA2-DT transcripts consisted of functional and full-length transcripts with little evidence for alternative mRNA isoforms in developing cotton fibers. Expression analyses showed that GhCesA2-A(T) and GhCesA2-D-T shared common temporal and spatial expression patterns, and they were highly and preferentially expressed during the cellulose biosynthesis stage in developing cotton fibers. The observations of higher expression levels of both GhCesA2-A(T) and GhCesA2-D-T in developing fibers of one near-isogenic line (NIL) with higher fiber bundle strength over the other NIL with lower fiber bundle strength suggested that the differential expression of genes associated with secondary cell wall cellulose biosynthesis in developing fiber might affect cotton fiber properties. Published by Elsevier B.V.