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P3N-PIPO (P3 N-terminal fused with Pretty Interesting Potyviridae ORF), the movement protein of potyviruses, is expressed as a translational fusion with the N-terminus of P3 in potyviruses. As reported in previous studies, P3N-PIPO is expressed via transcriptional slippage at a conserved G2A6 slippery site in the genus Potyvirus. However, it is still unknown whether a similar expression mechanism of P3N-PIPO is used in the other genera of the family Potyviridae. Moreover, due to the extremely low expression level of P3N-PIPO in natural virus-infected plants, the peptides spanning the slippery site which provide direct evidence of the slippage at the protein level, have not been identified yet. In this study, a potato virus X (PVX)-based expression vector was utilized to investigate the expression mechanism of P3N-PIPO. A high expression level of the P3N-PIPO(WT) of turnip mosaic virus (TuMV, genus Potyvirus) was observed based on the PVX expression vector. For the first time, we successfully identified the peptides of P3N-PIPO spanning the slippery site by mass spectrometry. Likewise, the P3N-PIPO(WT) of wheat yellow mosaic virus (WYMV, genus Bymovirus) was also successfully expressed using the PVX expression vector. Integrated proteome and transcriptome analyses revealed that WYMV P3N-PIPO was expressed at the conserved G2A6 site through transcriptional slippage. Moreover, as revealed by mutagenesis analysis, Hexa-adenosine of the G2A6 site was important for the frameshift expression of P3N-PIPO in WYMV. According to our results, the PVX-based expression vector might be used as an excellent tool to study the expression mechanism of P3N-PIPO in Potyviridae. To the best of our knowledge, this is the first experimental evidence for the expression mechanism of P3N-PIPO in the genus Bymovirus, the only genus comprising bipartite virus species in the family Potyviridae.

BWMK1,a first reported rice MAPK gene,was transcriptionally activated by blast fungus infection and wounding.To make a further understanding about the BWMK1-mediated defense signaling,we identified 7 BWMK1 interacting genes by yeast two-hybrid screening,designate BWIP1~BWIP7,and selected BWIP4 for further functional characterization.Through Agrobacterium mediated transformation method,we generated overexpression and RNAi transgenic plant using a japonica cultivar nipponbare as a receptor.The GUS assay and PCR results showed that the target gene had been intergrated into receptor.Further expression analysis was confirmed by RT-PCR.These transgenic lines provided us a good material for in-deepth function analysis of BWIP4.

914 marks(848 SSR and 66 SFP)were used to find the genomic polymorphism between the blast resistant rice variety Xiangzi3150 and the blast susceptible variety CO39.The results showed that expected bands were amplified from 96.39% of 881 markers(815 SSR and 66 SFP),among which 220 polymorphic tags were identified and 24.10% were.The polymorphism rate of the SSR mark(23.58%) was lower than that of the SFP mark(30.30%).The rate of polymorphic marks on the 12 chromosomes was different.Chromosome 10 had the highest rate(30.00%) and chromosome 9 had the lowest rate(14.55%).SSR marks with different units also showed a significant difference in polymorphism rate.The SSR marks with tetranucleotide repeats had the highest polymorphism rate(27.96%),followed by the repetitive dinucleotide,repetitive trinucleotide and repetitive single-nucleotide tags,respectively.

The components in plant signal transduction pathways are intertwined and affect each other to coordinate plant growth, development, and defenses to stresses. The role of ubiquitination in connecting these pathways, particularly plant innate immunity and flowering, is largely unknown. Here, we report the dual roles for the Arabidopsis (Arabidopsis thaliana) Plant U-box protein13 (PUB13) in defense and flowering time control. In vitro ubiquitination assays indicated that PUB13 is an active E3 ubiquitin ligase and that the intact U-box domain is required for the E3 ligase activity. Disruption of the PUB13 gene by T-DNA insertion results in spontaneous cell death, the accumulation of hydrogen peroxide and salicylic acid (SA), and elevated resistance to biotrophic pathogens but increased susceptibility to necrotrophic pathogens. The cell death, hydrogen peroxide accumulation, and resistance to necrotrophic pathogens in pub13 are enhanced when plants are pretreated with high humidity. Importantly, pub13 also shows early flowering under middle- and long-day conditions, in which the expression of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 and FLOWERING LOCUS T is induced while FLOWERING LOCUS C expression is suppressed. Finally, we found that two components involved in the SA-mediated signaling pathway, SID2 and PAD4, are required for the defense and flowering-time phenotypes caused by the loss of function of PUB13. Taken together, our data demonstrate that PUB13 acts as an important node connecting SA-dependent defense signaling and flowering time regulation in Arabidopsis.