Abstract:
【Objective】 To investigate the effects of the photosynthetic bacteria
Rhodopseudomonas palustris PSB06 Atp2 protein on the growth,defence enzyme activity and the transcript levels of defense-related genes in rice,and to provide theoretical basis for the popularization of the use of biocontrol bacteria in rice. 【Method】 Rice variety CO-39 was used as the test material,and rice seeds and leaves were treated with 3 treatment solutions of 0(distilled water,CK),20 and 50 μg/mL Atp2 protein,the chlorophyll a/b and the hydrogen peroxide(H
2O
2)content were detected,as well as the activities of rice defense-related enzymes such as peroxidase(POD),catalase(CAT),superoxide dismutase(SOD), glutathione reductase(GR),phenylalanine ammonia-lyase(PAL),polyphenol oxidase(PPO)in rice,and the transcript levels of defense-related genes(
OsWRKY70,OsLOX1,OsAOS2,OsPR1a,OsCHT1 and
OsPAL1)in rice were detected by real-time fluorescence quantitative PCR. 【Result】 Compared with CK,chlorophyll a/b was significantly(
P<0.05,the same below)or extremely significantly(
P<0.01,the same below)increased in rice after Atp2 protein treatment of rice leaves,while chlorophyll a/b did not change significantly after treatment of seeds(
P>0.05);H
2O
2 content in rice was elevated in all Atp2 protein treatments,with extremely significant elevation in the content of H
2O
2 after treatment of leaves; POD and CAT activities in rice were significantly or extremely significantly decreased after Atp2 protein treatment;SOD, GR and PAL activities in rice were extremely significantly increased after Atp2 protein treatment;PPO activity in rice was significantly or extremely significantly increased after Atp2 protein treatment of seeds,whereas PPO activity was signifi-cantly or extremely significantly decreased after treatment of leaves. After Atp2 protein treatment,expressions of rice defense genes
OsWRKY70,OsLOX1,OsAOS2(except 50 μg/mL Atp2 protein treated rice leaves),
OsPR1a and
OsCHT1 were all up-regulated,of which the expression of
OsWRKY70,OsLOX1 and
OsCHT1 genes were either significantly or extremely significantly up-regulated;the expression of
OsPAL1 gene was extremely significantly up-regulated after the treatment of seeds with Atp2 protein,and
OsPAL1 gene expression was extremely significantly up-regulated after the treatment of leaves. 【Conclusion】 The
R. palustris PSB06 Atp2 protein of
R. palustris has good growth-promoting and stressresistant effect on rice,which has the potential for promotion and application.