Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype.

Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B.

Two new species of the genus Micromonospora: Micromonospora palomenae sp. nov. and Micromonospora harpali sp. nov. isolated from the insects.

Two novel actinobacteria, strains NEAU-CX1(T) and NEAU-JC6(T), were isolated from nymphs of stinkbug (Palomena viridissima Poda) and a beetle (Harpalus sinicus Hope), respectively, collected from Harbin, Heilongjiang Province, China. A polyphasic study was carried out to establish the taxonomic positions of these strains. The phylogenetic analysis based on 16S rRNA gene sequence of strain NEAU-CX1(T) showed it to be most closely related to Micromonospora coxensis JCM 13248(T) (99.3 % sequence similarity), Micromonospora purpureochromogenes DSM 43821(T) (99.1 %) and Micromonospora halophytica JCM 3125(T) (98.6 %), and that of strain NEAU-JC6(T) to Micromonospora haikouensis DSM 45626(T) (99.3 %), Micromonospora carbonacea JCM 3139(T) (99.1 %) and Micromonospora krabiensis JCM 12869(T) (99.1 %). The phylogenetic analysis based on gyrB gene sequence of strain NEAU-CX1(T) showed it to be most closely related to M. purpureochromogenes DSM 43821(T) (98.0 % sequence similarity), and that of strain NEAU-JC6(T) to M. haikouensis DSM 45626(T) (99.0 %) and M. carbonacea JCM 3139(T) (98.0 %). A combination of DNA-DNA hybridization results and cultural and physiological properties indicated that the two strains can be distinguished from their closest phylogenetic relatives. Thus, strains NEAU-CX1(T) and NEAU-JC6(T) represent two novel species of the genus Micromonospora, for which the names Micromonospora palomenae sp. nov. and Micromonospora harpali sp. nov. are proposed. The type strains are NEAU-CX1(T) (=CGMCC 4.7175(T) = JCM 30056(T)) and NEAU-JC6(T) (=CGMCC 4.7173(T) = JCM 30055(T)).