title: Overexpressing CYP71Z2 enhances resistance to bacterial blight by suppressing auxin biosynthesis in rice.
abstract: BACKGROUND
  The hormone auxin plays an important role not only in the growth and development of rice, but also in its defense responses. We've previously shown that the P450 gene CYP71Z2 enhances disease resistance to pathogens through regulation of phytoalexin biosynthesis in rice, though it remains unclear if auxin is involved in this process or not.
  
  
  RESULTS
  The expression of CYP71Z2 was induced by Xanthomonas oryzae pv. oryzae (Xoo) inoculation was analyzed by qRT-PCR, with GUS histochemical staining showing that CYP71Z2 expression was limited to roots, blades and nodes. Overexpression of CYP71Z2 in rice durably and stably increased resistance to Xoo, though no significant difference in disease resistance was detected between CYP71Z2-RNA interference (RNAi) rice and wild-type. Moreover, IAA concentration was determined using the HPLC/electrospray ionization/tandem mass spectrometry system. The accumulation of IAA was significantly reduced in CYP71Z2-overexpressing rice regardless of whether plants were inoculated or not, whereas it was unaffected in CYP71Z2-RNAi rice. Furthermore, the expression of genes related to IAA, expansin and SA/JA signaling pathways was suppressed in CYP71Z2-overexpressing rice with or without inoculation.
  
  
  CONCLUSIONS
  These results suggest that CYP71Z2-mediated resistance to Xoo may be via suppression of IAA signaling in rice. Our studies also provide comprehensive insight into molecular mechanism of resistance to Xoo mediated by IAA in rice. Moreover, an available approach for understanding the P450 gene functions in interaction between rice and pathogens has been provided.
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Fangquan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Fangjun
authors.initials: F
authors.lastname: Fan
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Jinyan
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Fengquan
authors.initials: F
authors.lastname: Liu
authors.affiliation: Institute of Food Crops, Jiangsu Academy of Agricultural Sciences/Nanjing Branch of Chinese National Center for Rice Improvement/Jiangsu High Quality Rice R&D Center, Nanjing 210014, China.
authors.forename: Weigong
authors.initials: W
authors.lastname: Zhong
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D060467:Disease Resistance / Q000502:physiology*; D054884:Host-Pathogen Interactions; D007210:Indoleacetic Acids / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism* / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology*; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D053719:Tandem Mass Spectrometry; D014974:Xanthomonas / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D003577:Cytochrome P-450 Enzyme System