Relationship Of A Pentatricopeptide Repeat Like Gene PPRs With The Regμlation Of Rosette Leaf Senescence In Arabidopsis

PPR (pentatricopeptide repeats) gene family is one of the largest gene families in land plants, its members play important functions in the reg μ lation of plant growth, development and in response to various internal and external environmental stresses. This study focus on the relationship of a PPR gene (called PPRs) with the reg μ lations of rosette leaf senescence progress in Arabidopsis. The main res μ Its are described as follows:1. The expression analysis of PPRs gene in Arabidopsis were conducted by qRT-PCR with NtGAPDH as reference gene. It was found that this gene was expressed in various tissues of 7-week-old Arabidopsis plants, and its expression in rosette leaves, flower organs and siliques are higher than in the other tissues. In the rosette leaves, its expression was quickly decreased when the leaves initiated the senescence progress after the transition from vegetative to reproductive status.2. We obtained PPRs gene overexpression (OE-PPRs) and antisense inhibition (antisense-PPRs, AN-PPRs) T-DNA insertion lines via BASTA resistance selection and PCR identifications.3. We identified the localization of PPRs-GFP fusion protein in a cell via transient transformation of onion epidermal and tobacco leaves cells. The res μ Its showed that the PPRs-GFP fluorescence was present in chloroplast.4. We observed the senescence phenotypes of rosette leaves of PPRs transgenic plants. It was showed that the rosette leaves of overexpression (OE-PPRs) line showed no significant difference in senescence compared with wildtype and inhibition (antisense-PPRs, AN-PPRs) line. And compared to WT, the seventh true leaf of overexpression (OE-PPRs) lines showed no significant difference in chlorophyll content, the FV/FM value has no significant difference in overexpression (OE-PPRs), antisense inhibition (antisense-PPRs, AN-PPRs) and wildtype plants.5. After the treatments with different kinds of senescence inducible or inhibitory factors in 4-week-old rosette leaves in vitro, it was showed that the expression of PPRs gene was decreased to the 6-week-old plant level in the control, but the treatments with jasmonic acid (JA), cold, hot and drought co μ Id significantly delayed this decrease of PPRs expression. After the treatment with JA for three days, the leaves of PPRs over-expressing line showed obviously delayed leaf senescence morphology compared to the wildtype plant. By detecting the expression of some leaf senescence-associated genes in PPRs over-expressing and wildtype plants, it was shown that the expression of some genes were really significantly changed in the transgenic line compared to the wildtype. These res μ Its indicate that the PPRs gene in Arabidopsis may participate in the reg μ lation of senescence-related factors induced rosette leaf senescence in vivo.