The complete genomic sequence of a telosma mosaic virus (TeMV) isolate (named PasFru), identified in passion fruit in China, was determined. The entire RNA genome of PasFru comprises 10,049 nucleotides (nt) excluding the poly(A) tail and encodes a polyprotein of 3,173 amino acids (aa), flanked by 5' and 3' untranslated regions (UTR) of 276 and 251 nt, respectively. Compared with the previous TeMV isolate Hanoi from Telosma cordata, the only documented isolate with the entire genome sequence annotated, PasFru had an extra 87 nt and 89 aa residues at the 3'-end of 5'UTR and the N-terminus of the P1 protein, respectively, which contributed to the genome size difference between PasFru and Hanoi (10,049 nt versus 9,689 nt). Pairwise sequence comparisons showed that PasFru shares 73.6% nt and 80.9% aa sequence identity with the Hanoi isolate at the whole-genome and polyprotein level, respectively, and these values are below the corresponding threshold values for species demarcation in the family Potyviridae. These data suggest that TeMV-PasFru should be classified as a new member of the genus Potyvirus.

Hydrosilylation of unsaturated carbon-carbon bonds with hydrosilanes is a very important process to access organosilicon compounds and ranks as one of the most fundamental reactions in organic chemistry. However, catalytic asymmetric hydrosilylation of activated alkenes and internal alkenes has proven elusive, due to competing reduction of carbon-carbon double bond or isomerization processes. Herein, we report a highly enantioselective Si-C coupling by hydrosilylation of carbonyl-activated alkenes using a palladium catalyst with a chiral TADDOL-derived phosphoramidite ligand, which inhibits O-hydrosilylation/olefin reduction. The stereospecific Si-C coupling/hydrosilylation of maleimides affords a series of silyl succinimides with up to 99% yield, >99:1 diastereoselectivity and >99:1 enantioselectivity. The high degree of stereoselectivity exerts remote control of axial chirality, leading to functionalized, axially chiral succinimides which are versatile building blocks. The product utility is highlighted by the enantioselective construction of N-heterocycles bearing up to three stereocenters.

Areca palm (Areca catechu L.), one of the two most important commercial crops in Hainan, China, has been severely damaged by a variety of pathogens and insects. Here, we report a new disease, tentatively referred to as areca palm necrotic ringspot disease (ANRSD), which is highly epidemic in the main growing regions in Hainan. Transmission electron microscopy observation and small RNA deep sequencing revealed the existence of a viral agent of the family Potyviridae in a diseased areca palm plant (XC1). The virus was tentatively named areca palm necrotic ringspot virus (ANRSV). Subsequently, the positive-sense single-stranded genome of ANRSV isolate XC1 was completely determined. The genome annotation reveals the existence of two cysteine proteinases in tandem (HC-Pro1 and HC-Pro2) in the genomic 5' terminus of ANRSV. Sequence comparison and phylogenetic analysis suggested the taxonomic classification of ANRSV into the recently proposed genus 'Arepavirus' in the family Potyviridae. Given the close relationship of ANRSV with the other newly reported arepavirus (ANSSV), the exact taxonomic status of ANRSV needs to be further investigated. Eventually, a reverse-transcription (RT)-PCR assay for ANRSV-specific detection was developed and a close association between ANRSV and the disease was found.

A novel virus, tentatively named "areca palm necrotic spindle-spot virus" (ANSSV), was identified in Areca catechu L. in Hainan, China, and its complete genomic sequence was determined. Its positive-sense single-stranded RNA genome is comprised of 9,437 nucleotides (nt), excluding the poly (A) tail, and contains one large open reading frame encoding a polyprotein of 3,019 amino acids (aa). A Blastp search showed that the polyprotein of ANSSV shared a maximum of 31%-32% aa sequence identity (with 86%-95% coverage) with all seven known macluraviruses. Nucleotide sequence comparison of the ORF of ANSSV to those of macluraviruses revealed identities ranging from 41.0% to 44.6%, which is less than the inter-genus identity values for the family Potyviridae. Phylogenetic analysis based on either the aa or nt sequence of the polyprotein did not cluster ANSSV into any established or unassigned genus of the family Potyviridae. Therefore, we suggest that ANSSV is the first member of a previously unrecognized genus of the family Potyviridae.

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