RESUMO
Chitinase is an important pathogenesis-related protein in plants, and it can accumulate when induced by salicylic acid (SA) or other elicitors. Here, we found that chitinase mRNA levels were 4.5-times greater when peanut seedlings were sprayed with 1.5 mM SA, as compared to water. The upstream promoter sequence of the chitinase gene was cloned by TAIL-PCR and the potential cis-regulatory elements in this promoter were predicted by the cis-element databases PLACE and plantCARE. Elements in the promoter related to SA induction and disease resistance response included AS-1, GT1-motif, GRWAAW, TGTCA, W-box, and WB-box. The full-length promoter (P) and a series of 5'-deleted promoters (P1-P5) were cloned and then substituted for the 35S promoter of pCAMBIA1301-xylA, which carries the xylose isomerase gene as the selectable marker and GUS as the reporter gene. Six plant expression vectors (pCAMBIA1301-xylA-P-pCAMBIA1301-xylA-P5) were obtained. The six expression vectors were then transferred into onion epidermal cells and peanut plants by Agrobacterium-mediated transformation. Both the full-length and deleted promoters resulted in GUS staining of the onion epidermis cells when induced by SA. In onion epidermis cells, GUS enzyme activity was greater after SA induction. In transgenic peanut plants, GUS mRNA levels were greater after SA induction. Consideration of the cis-regulatory elements predicted by PLACE and plantCARE suggested that AS-1, GRWAAW, and W-box are positive regulatory elements in P2 and P3 and that GT1-motif and TGTCA are negative regulatory elements between P and P2.
Assuntos
Arachis/enzimologia , Arachis/genética , Quitinases/genética , Regiões Promotoras Genéticas/genética , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/genéticaRESUMO
Two genetic linkage maps of cultivated maize inbred lines and teosinte species were constructed. One population comprised 81 F(2) individuals derived from a cross between maize inbred line B73 and Zea mays ssp parviglumis, while the second consisted of 63 backcross individuals from a cross of maize inbred line B73 with Z. mays ssp diploperennis. In the B73 x Z. mays ssp parviglumis F(2) population, 172 simple sequence repeat (SSR) markers were mapped to 10 chromosomes, which covered 2210.8 cM. In the B73 x Z. mays ssp diploperennis backcross population, 258 SSR markers were mapped to 10 chromosomes, covering 1357.7 cM. Comparison of the two maps revealed that the total map length of Z. mays ssp diploperennis covers 1357.7 cM, which is about 61.4% of that of Z. mays ssp parviglumis (2210.8 cM). Extensive segregation distortion regions were found on chromosomes 1, 2, 3, 5, 6, 7, and 10 in the B73 x Z. mays ssp parviglumis F(2) population and on chromosomes 1-5 and 8-10 in the B73 x Z. mays ssp parviglumis backcross population. Segregation distortion analysis confirmed that the segregation distortion ratio in the interspecific population B73 x Z. mays ssp diploperennis was higher than in B73 x Z. mays ssp parviglumis. We found that the recombination distances are highly variable in these genetic crosses between cultivated and wild species of maize.