Molecular Cloning Of PtIAA1 And PtABP1 And Their Expression In Poplar

Wood formation is a complex process composing many biological events, of which are strictly regulated by corresponding genes. In order to improve wood quality with molecular breeding techniques, it is necessary to deeply understand the molecular mechanisms of wood formation, to study the function of key genes controlling wood formation and interaction mechanisms of these genes. Ultimately, it is desirable to effectively manipulate the key genes involved in wood formation and produce the genetically modified trees with improved wood quality. Auxin plays a key role in regulating wood formation through its effects on cambial activity and vascular tissue differentiation in plants: controlling the period of cambial activity, maintaining the morphology and arrange orientation of fusiform cells, regulating the differentiation of phloem and xylem. The previous reports in model plant Arabidopsis thaliana revealed that ABP and ARP could effectively regulate the development and differentiation of vascular tissue by involving in the transport of Auxin. To explore the role of PtIAA1 involved in cambial activity and wood formation, two genes, ABP1 and ARP1 were isolated using reverse transcriptase-PCR method. The expression patterns of these two genes in wood plant poplar were studied by using methods of both reverse transcriptase-PCR and gene transformation. The preliminary result showed that both ABP and ARP have important roles in cambial activity and wood formation processes. The major findings are described as the followings:1. Anx/1AA genes play critical roles in IAA signaling. A cDNA clone encoding PtIAA1 was isolated from the cDNA prepared from cambial zone of P. tomentosa by the reverse transcriptase -PCR method. The cDNA is 764 bp in length with an open reading frame which is capable of encoding a protein of 201 amino acid (aa). The tissue-specific expression pattern was studied by the reverse transcriptase -PCR method. Results showed that the transcript levels of PtIAAl were most abundant in the active cambium tissues, low in roots, immaturity xylem and mature xylem, scarce in phloem. To explore the role of PtIAAl in cambial activity and vascular...