Effects Of Adversity Stress On The Expression Of ZlChi Genes And Physiological Activity In Zizania Latifolia

Zizania latifolia is a perennial herbaceous plant of Zizania in the Gramineae family,which is the second largest aquatic vegetable in China after the lotus root in the planting area.It is not only rich in various nutritional elements,but also has medicinal value,health care effect and high economic benefits.Ustilago esculenta,belonging to Ustilaginales Ustilaginaceae,is an endophytic fungus in Z.latifolia.It interacts with Z.latifolia to form an edible fleshy stem.At present,the symbiosis mechanism between Z.latifolia and U.esculenta is still unclear.In this study,E jiao No.1 was used as the test material to detect the expression of chitinase gene in the leaves of Z.latifolia by RT-q PCR under abiotic stress.And the 5-leaf stage male Jiaobai seedlings were used as experimental materials to explore the effect of artificial inoculation with U.esculenta on the expression of chitinase genes in male Jiaobai leaves,as well as the effect of artificial inoculation with U.esculenta on the disease resistance-related enzymes(chitinase,β-1,3-glucanase),phenylpropane metabolism-related enzymes(PPO,PAL),antioxidant enzymes(APX,CAT,POD,SOD)activity and the influence of membrane lipid peroxidation products(MDA)content.In addition,the roots and stems of male Jiaobai 15 days after inoculation were taken for the paraffin section to detect the changes of smut fungus in the male Jioabai.The main results are as follows:1.The effect of abiotic stress on the expression of chitinase genes in Z.latifolia leaves.The experiment performed abiotic stress treatment on the 5-leaf stage Z.latifolia and detected the expression of chitinase genes by RT-q PCR.The results showed that most ZlChis responded to abiotic stress within 6 h,although some ZlChis reached peak expression at 12 h or 18 h of abiotic stress treatment.Expression of ZlChi2 and ZlChi5 were up-regulated,ZlChi1 and ZlChi3 were down-regulated under each stress treatment,while ZlChi10 or ZlChi11 were not detected under any conditions.2.Effect of U.esculenta infection on chitinase genes expression in the leaves of male Jiaobai.5-leaf stage male Jiaobai were inoculated with U.esculenta,and the expression of chitinase genes in the leaves of male Jiaobai were detected by RT-q PCR.The results showed that most ZlChis responded to smut fungus infection.Expression of ZlChi1,ZlChi6,ZlChi8 and ZlChi11 were up-regulated significantly,and reached relative expression peaks at 3 d,6 h,5 d,and 3 h respectively,while other ZlChis were low or down-regulated,ZlChi2,ZlChi5 and ZlChi9 were not detected after smut fungus infection.3.Changes in the activity of disease-resistant enzymes.After infection,the activity of chitinase and β-1,3-glucanase in the leaves of male Jiaobai reached their peak at 3 h,and showed a trend of gradual decrease over time.Chitinase activity was significantly higher than the control at 12 h,β-1,3-glucanase activity was significantly higher than that of the control at 3 h,and was significantly lower than that of the control at 12 h.The difference between the two groups at other times was not significant.4.Changes in enzyme activities related to phenylpropane metabolism.The PPO activity in the leaves of male Jiaobai was higher than that of the control at 12 h,24 h and 3 d,but the difference was not significant.The PAL activity was higher than that of the control from 6 h,and the activity reached its peak at 3 d,which is significantly higher than that of the control.5.Changes in antioxidant enzyme activity and MDA content.The APX activity reached its peak at 12 h,which was significantly higher than that of the control.And at 3 h,the POD activity reached the highest,which was significantly higher than that of the control,and at the same time,the CAT activity reached the highest value.At 18 h,the SOD activity of male Jiaobai leaves reached its peak,but it was not significantly different from the control.MDA content was not significantly different from the control after treatment.6.Detection of U.esculenta in inoculated plants.The genomic DNA of the roots and stems of male Jiaobai seedlings at 15 days after inoculation were extracted,and the content of smut fungus was detected by q PCR.The results showed that U.esculenta existed in the roots of male Jiaobai,but not in the stems.The paraffin section showed that there were a lot of fungal hyphae in the roots of male Jiaobai seedlings at 15 days after inoculation,but few in the control.