Based on the foundation laid by the h-index we introduce and study the R-and AR-indices. These new indices eliminate some of the disadvantages of the h-index, especially when they are used in combination with the h-index. The R-index measures the h-core's citation intensity, while AR goes one step further and takes the age of publications into account. This allows for an index that can actually increase and decrease over time. We propose the pair (h, AR) as a meaningful indicator for research evaluation. We further prove a relation characterizing the h-index in the power law model. h-index, A-index, R-index, AR-index, g-index, performance evaluation, power law

Plant viruses are excellent tools for studying microbial-plant interactions as well as the complexities of host activities. Our study focuses on the role of C2 encoded by Beet severe curly top virus (BSCTV) in the virus-plant interaction. Using BSCTV C2 as bait in a yeast two-hybrid screen, a C2-interacting protein, S-adenosyl-methionine decarboxylase 1 (SAMDC1), was identified from an Arabidopsis thaliana cDNA library. The interaction was confirmed by an in vitro pull-down assay and a firefly luciferase complemention imaging assay in planta. Biochemical analysis further showed that the degradation of the SAMDC1 protein was inhibited by MG132, a 26S proteasome inhibitor, and that C2 could attenuate the degradation of the SAMDC1 protein. Genetic analysis showed that loss of function of SAMDC1 resulted in reduced susceptibility to BSCTV infection and reduced viral DNA accumulation, similar to the effect of BSCTV C2 deficiency. Bisulfite sequencing analysis further showed that C2 deficiency caused enhanced DNA methylation of the viral genome in infected plants. We also showed that C2 can suppress de novo methylation in the FWA transgenic assay in the C2 transgene background. Overexpression of SAMDC1 can mimic the suppressive activity of C2 against green fluorescent protein-directed silencing. These results suggest that C2 interferes with the host defense mechanism of DNA methylation-mediated gene silencing by attenuating the 26S proteasome-mediated degradation of SAMDC1.

SummaryThe C4 protein from Curtovirus is known as a major symptom determinant, but the mode of action of the C4 protein remains unclear. To understand the mechanism of involvement of C4 protein in virus-plant interactions, we introduced the C4 gene from Beet severe curly top virus (BSCTV) into Arabidopsis under a conditional expression promoter; the resulting overexpression of BSCTV C4 led to abnormal host cell division. RKP, a RING finger protein, which is a homolog of the human cell cycle regulator KPC1, was discovered to be induced by BSCTV C4 protein. Mutation of RKP reduced the susceptibility to BSCTV in Arabidopsis and impaired BSCTV replication in plant cells. Callus formation is impaired in rkp mutants, indicating a role of RKP in the plant cell cycle. RKP was demonstrated to be a functional ubiquitin E3 ligase and is able to interact with cell-cycle inhibitor ICK/KRP proteins in vitro. Accumulation of the protein ICK2/KRP2 was found increased in the rkp mutant. The above results strengthen the possibility that RKP might regulate the degradation of ICK/ KRP proteins. In addition, the protein level of ICK2/KRP2 was decreased upon BSCTV infection. Overexpression of ICK1/KRP1 in Arabidopsis could reduce the susceptibility to BSCTV. In conclusion, we found that RKP is induced by BSCTV C4 and may affect BSCTV infection by regulating the host cell cycle.

The calculation of Hirsch's h-index is a detail-ignoring way, therefore, single h-index could not reflect the difference of time spans for scientists to accumulate their papers and citations. In this study the h-index sequence and the h-index matrix are constructed, which complement the absent details of single h-index, reveal different increasing manner and the increasing mechanism of the h-index, and make the scientists at different scientific age comparable.