摘要
The Arabidopsis Di19 （Drought-induced） gene family encodes seven Cys2/His2-type zinc-finger proteins, most with unknown functions. Here, we report that Di19 functioned as a transcriptional regulator and was involved in Arabidopsis responses to drought stress through up-regulation of pathogenesis-related PR1, PR2, and PR5 gene expres- sions. The Di19 T-DNA insertion mutant di19 was much more sensitive to drought stress, whereas the Di19-overexpressing lines were much more tolerant to drought stress compared with wild-type plants. Di19 exhibited transactivation activity in our yeast assay, and its transactivation activity was further confirmed in vivo. DNA-binding analysis revealed that Di19 could bind to the TACA（A/G）T element and chromatin immunoprecipitation （CHIP） assays demonstrated that Di19 could bind to the TACA（A/G）T element within the PR1, PR2, and PR5 promoters, qRT-PCR results showed that Di19 promoted the expressions of PR1, PR2, and PRS, and these heightened expressions were enhanced by CPK11, which interacted with Di19 in the nucleus. Similarly to the Di19-overexpressing line, PRI-, PR2-, and PRS-overexpressing lines also showed the drought-tolerant phenotype. The pre-treatment with salicylic acid analogs INA can enhance plants＇ drought tolerance. Taken together, these data demonstrate that Di19, a new type of transcription factor, directly up-regulates the expres- sions of PR1, PR2, and PR5 in response to drought stress, and its transactivation activity is enhanced by CPK11.
The Arabidopsis Di19 （Drought-induced） gene family encodes seven Cys2/His2-type zinc-finger proteins, most with unknown functions. Here, we report that Di19 functioned as a transcriptional regulator and was involved in Arabidopsis responses to drought stress through up-regulation of pathogenesis-related PR1, PR2, and PR5 gene expres- sions. The Di19 T-DNA insertion mutant di19 was much more sensitive to drought stress, whereas the Di19-overexpressing lines were much more tolerant to drought stress compared with wild-type plants. Di19 exhibited transactivation activity in our yeast assay, and its transactivation activity was further confirmed in vivo. DNA-binding analysis revealed that Di19 could bind to the TACA（A/G）T element and chromatin immunoprecipitation （CHIP） assays demonstrated that Di19 could bind to the TACA（A/G）T element within the PR1, PR2, and PR5 promoters, qRT-PCR results showed that Di19 promoted the expressions of PR1, PR2, and PRS, and these heightened expressions were enhanced by CPK11, which interacted with Di19 in the nucleus. Similarly to the Di19-overexpressing line, PRI-, PR2-, and PRS-overexpressing lines also showed the drought-tolerant phenotype. The pre-treatment with salicylic acid analogs INA can enhance plants＇ drought tolerance. Taken together, these data demonstrate that Di19, a new type of transcription factor, directly up-regulates the expres- sions of PR1, PR2, and PR5 in response to drought stress, and its transactivation activity is enhanced by CPK11.
基金
This work was supported by the Chinese National Key Basic Research Project （No. 2011CB100305） and the National Natural Science Foundation of China （No. 30970220）.The authors thank Dr Chen Shou-Yi （Institute of Genetics and Developmental Biology, China） for assistance with the trans- activation activity assay in Arabidopsis protoplasts and Dr Lin Hong-Xuan （Shanghai Institute of Plant Physiology and Ecology, China） for providing the bacterial one-hybrid system. No conflict of interest declared.
