Differential Gene Expression Of Arabidopsis Against Infection Of Alternaria Porri

Resistance responses were studied in different Arabidopsis ecotypes after being inoculated by some important plant pathogens. According to the results, molecular mechanisms of resistance and expression of the defense-related genes in resistance and susceptible Arabidopsis ecotypes were studied. Results followed in this paper.All the 11 Arabidopsis ecotypes tested were incompatible to Erysiphe convolvuli, Alternaria brassicicola, Setosphaeria turcica and Verticillium dahliae. Transgenic NahG and Col, Shakh-dara, Nd-1, WS-2 and Kas-1 ecotypes were all compatible to Sphaerotheca cucurbitae, Alternaria porri, Erysiphe cucurbitacearum and Alternaria solani. her ecotype was incompatible to Alternaria porri and Alternaria solani. C24, Est-1, Ws-0 and Bay-0 ecotypes were all incompatible to Sphaerotheca cucurbitae, Alternaria porri, Erysiphe cucurbitacearum and Alternaria solani.Changes of defense enzymes activities and non-enzyme component in the trangenic NahG and WS-2, Shakh-dara ecotypes were identified after being infected by Alternaria porri. CAT, PPO, SOD activities and MDA content had nearly relation to Arabidopsis against infection of Alternaria porri. The relation between POD, PAL activities and Arabidopsis against infection of Alternaria porri was unknown.Through modified method of DDRT-PCR, 135 differential expressed fragments were obtained from cDNA of different Arabidopsis ecotypes before and after inoculation. Among 135 differential expressed fragments, 38 cDNA fragments were hybridized to cDNA from inoculation and uninoculation plants. At the same time, all the differential expressed fragments were not hybridized to molecular markers of defense response (included PR-1, PR-2, PR-3, PR-4 and PDF1.2 genes). It concluded that PR-1, PR-2, PR-3, PR-4 and PDF1.2 genes were not expressed in Arabidopsis after inoculated by Alternaria porri. Dfferentially expressed fragments cloned and sequenced. Homologous results indicated that not only gene related to respiration was induced but genes related to Cytoskeleton assembly control protein (for example Sla1) and proteolysis or peptidolysis were also induced.Through the method of RACE, 5' full sequence of No 47 fragment was obtained. It probably has 77% homologous to Aspergillus nidulans and Neurospora crassa Cytoskeleton assembly control protein SLA1. It also has 36% homologous toSaccharomyces cerevisiae and yeast SLA1. At the same time, it has 86%^ 32% and 43% homologous to ORF64c of Pinus koraiensis, SH3 domain-containing protein SH3P17 of Homo sapiens and src-family protein tyrosine kinase of Strongylocentrotus purpuratus respectively.