Research In Mechanism Of Conferring Drought Tolerance In Maize (Zea Mays) Seeding By Endophytic Fungus Piriformospora Indica

Piriformospora indica colonized the roots of many plant, the formation of plant-microbe interactions symbiotic model promotes the plants growth, increase productions, inducing the plant to biotic and abiotic stress tolerance. P.indica expresses under drought conditions on corn physiological and biochemical indicators of gene expression, related to drought resistance, plant hormones and plant PCD (Program Cell Death) genes, physiological, molecular, signaling level. The evaluations of P.indica enhance maize drought resistance mechanism. The study about microorganism with plant interaction system enhanced drought resistance mechanism provides a new way of thinking. The study has laid superior foundation. The main findings are as follows:(1) On the form performance:under drought stress conditions, P.indica inoculated and non-inoculated plants are compared for many parameters, such as root length, root dry weight, root fresh weight, parameter were highly differences from each other. The number of leaves, leaf area, leaf chlorophyll content. The vaccinated were higher than non-inoculated corn, reached significant differences in the levels. The results show that P.indica can promote the growth of corn under the ground as well on the above portion of the ground, which promotes the growth of roots is the fundamental.(2) On the basis of antioxidant system:In the inoculation case of fungi dehydrated maize maintain high Proline content and low MDA content, while in 20%PEG-6000 stress, SOD, CAT and AsA-POD activities increased when the stress are for a long period of time. The inoculated maize leaf protective enzyme activity is compared to non-inoculated rise more rapidly and more accumulated more effective removal of reactive oxygen species, mitigation of cell damage caused by drought stress. P.indica can induce active oxygen scavenging mechanism maize start in dry conditions, maintain the balance of reactive oxygen species accumulation and removal, reduce the amount of reactive oxygen species, reduce lipid peroxidation in raising maize for drought tolerance.(3) Related gene expression:our study found that:CBL1, SDIR1, HAT, PLDδ, ANAC072, C1PK3, DREB2A, ERD1 these eight genes trend in maize root expression varies in 20% PEG-6000 analog drought stress treatment Oh-24h, all genes are up regulated. Dealing 3h in maize roots with P.indica inoculated, CBL1, SDIR1, HAT genes were significantly higher than non-vaccinated, especially CBL1, SDIR1, in dealing with 12h, the difference is even more significant. Expression of vaccinated and non-inoculated respectively 312.9 times,571.28 times when handling 3h to 6h, except PLDδ, almost all of the remaining gene expression decreased in the treatment 24h, the expression ANAC072, CIPK3, DREB2A, ERD1, HAT begin to rise again, and fungal inoculation. The expression of the roots of plants were non-inoculated 3.1 times,2.02 times and 2.86 times,2.3 times,4.4 times, these drought responsive genes in fungal expression non-inoculated maize plants root is relatively more lag.(4) Simulated drought in 15% PEG-6000 stress treament, the growth of plant height and root length of corn has obviously been inhibition relative to the control, indicating that the drought limit growth of maize; in the same processing conditions, vaccinated height and roots of plant with P.indica vaccinated are higher than the non-inoculated, which indicating that P.indica can reduce drought stress, and sustain the growth of maize for the future productivity.(5) Under the ongoing water stress, the maize leaves and roots accumulate large amounts of ABA to deal with drought stress three days after inoculation. Maize root with fungus ABA contents accumulated a large number of non-inoculated fungi maize plants in stress treatment five days after accumulation, response to water stress. The more sluggish performance in maize inoculated with the fungus non-inoculated maize plants compared to the ABA. Under normal growth conditions, the P.indic inoculated maize root and leaf NO content rise in the cell, with the pass of time gradually reduce. Inoculation of corn leaf NO content in cells as the extension of stress time and present the change trend of "increase-decrease-increase" trends, and the corn roots with the stress time present "increase-decrease" trends.(6) Under 200 μM of SNP treatment conditions, P.indica inoculated corn the expression of ABA key enzyme Zeaxanthin Epoxidase (ZEP) gene will increase in maize leaves and root cells, thereby P.indica promoting the ABA synthesis. NO treatment relative to the non-inoculated corn plants, inoculated with leaves and roots PCD inhibit the expression of gene Bax-I and plant gene Rp1-D21 HR up regulated, and the expression in advance; maize leaves and roots in a sustained high concentration NO under stress need to make adaptive response, so with NO processing time extended Bax-I, Rp1-D21 gene expression begin to drop.Based on the above findings strategies, the plant set up a feeling and conduction of drought signal system, a series of physiological or developmental mechanisms in response to stress, antioxidant enzyme system in maize leaves. P.indica target site of action induced by NO content of plant hormone ABA and the regulation of substances and expression series of related genes play a regulatory role in physiological processes associated tone holes, etc. confer maize for drought tolerance.