The Regulation Of Paclobutrazol To Mango Anthracnose And Differential Expression Analysis Of Resistance Gene In Mango Leaves Sprayed With Paclobutrazol

Paclobutrazol is a triazoles plant growth regulator developed in the80s. Paclobutrazol is endogenous GA3synthesis inhibitors. Paclobutrazol is widely used in the production of agriculture, to slow the growth of plants,inhibition of stem elongation, promote tillering, promote flowering and fruit setting and so on. On the agricultural production,we found paclobutrazol can reduce the plant disease.but there is no evidence to prove this phenomenon. In this paper, we used mango causal agent Colletotrichum gloeosporioides as test strain to study the effect of paclobutrazol to mango anthracnose and the inhibitory effect of paclobutrazol to Colletotrichum gloeosporioides. Used Semi-quantitative RT-PCR to study gene expression which coding immunity and defense. Use cDNA-AFLP to detect differentially expressed genes. Used Semi-quantitative RT-PCR to study differential expression gene.The main results as follows:1. The detached leaf method showed that700mg/L800mg/L900mg/L1000mg/L paclobutrazol can control extension of disease spot on the detached leaf in different degrees.But mango anthracnose significantly reduced after the detached leaf spray with800mg/L paclobutrazol.800mg/L paclobutrazol could inhibit the growth of hypha, make the spores deformity,the spores germinate unnormal and can not produce appressorium on the cellophane.The spore morphology is normal,spore can germinate and formed appressorium normally,but postponed one day of appressorium formation on the detached leaf treated with800mg/L paclobutrazol.Paclobutrazol showed weakly fungicidal effect on the life medium.Therefore, maybe paclobutrazol regulate plant disease resistant to inhibit Colletotrichum gloeosporioides infected.2. There is no visible difference expression about defensin gene deal with paclobutrazol only.but the expression of PAL and PDF1.2is higher than contrast after inoculated lday2day. But the expression of PR is higher than contrast after inoculated lday deal with paclobutrazol. The expression of PPO appear two peak after inoculated3day and5day the expression of PPO is obvious higher than contrast after inoculated3day.The expression of Chi-E is lower than contrast in each period.The result showed that the expression defensin gene can be induced by paclobutrazol and pathogenic fungi. Paclobutrazol can reduce the infection rate. the infection rate is reduced that is why Chi-E expression lower than contrast3. We got118difference expression DNA fragment. There is17.8percent fragments is related with disease-resistant defense signal transduction transcription and regulation.There is5.2percent fragments is related with photosynthesis.thses different expression DNA fragment may is the reason paclobutrazol reduce the plant disease.4. Used Semi-quantitative RT-PCR to study gene expression of different expression DNA fragment,we found photosynthesis and drought-resistant ability of plant is improved deal with paclobutrazoland pathogenic fungi.The expression of two different expression DNA fragment which have high homology with F-box and ubiquitin-fold modifier-conjugating enzyme is higher than contrast after deal with paclobutrazoland pathogenic fungi.we guess paclobutrazoland pathogenic fungi can induce ubiquitin proteasome pathway to improve the abilitiy of disease resistance.