Identification of two distinct begomoviruses infecting Malvastrum coromandelianum

Malvastrum coromandelianum is a common weed plant frequently found around agricultural fields. Three virus isolates (Y249, Y278 and Y281) were obtained from M. coromandelianum with yellow vein symptoms in Honghe and Baoshan, Yunnan Province, China. Specific 500 bp products were amplified from total DNA extracts using universal primers for members of the genus Begomovirus. The complete viral genome sequences of both Y278 and Y281 were determined to be 2743 nucleotides, and that of Y249 was determined to be 2740 nucleotides. Sequence alignments and phylogenetic analyses support the proposal of creating new species in the genus Begomovirus, for which the name malvastrum yellow vein Baoshan virus (MaYVBsV) is proposed for Y278 and Y281, and malvastrum yellow vein Honghe virus (MaYVHhV) is proposed for Y249.

Complete genome sequence of a previously undescribed monopartite begomovirus and betasatellite infecting Malvastrum coromandelianum in Cambodia

A previously undescribed monopartite begomovirus was identified from Malvastrum coromandelianum plants exhibiting yellow vein symptoms characteristic of begomoviruses, in Kampot province, Cambodia. The apparently full-length viral component was cloned and sequenced following enrichment of circular DNA by rolling circle amplification and restriction enzyme digestion. The genome of the virus was 2,737 nucleotides in length (KP188831), and exhibited an organization like that of other monopartite begomoviruses, sharing the highest nt identities of 87.7% with Ageratum yellow vein virus (AM940137). A satellite molecule was amplified from total DNA by PCR amplification with the betasatellite-specific primer pair β01/β02. The satellite molecule (1,346 nt, KP188832) had a structure characteristic like other betasatellites associated with begomoviruses, and shared the highest nt identity of 84.8% with Malvastrum yellow vein betasatellite (MN205547). According to the criteria established for species demarcation for classification of begomoviruses ( Geminiviridae ) and betasatellites ( Tolecusatellitidae ), respectively, the virus isolate from M. coromandelianum in Cambodia is a previously undescribed novel monopartite begomovirus species，for which the name Malvastrum yellow vein Cambodia virus (MaYVCV) is proposed, whereas, the betasatellite is identified as an previously undescribed novel betasatellite species, for which the name Malvastrum yellow vein Cambodia batesatellite (MaYVKHB) is proposed.

In-vitro screening of antihelmintic and antibacterial activity of malvastrum coromandelianum leaves

The main objective of the work is to investigate the antithelmintic and antibacterial activity of the Malvastrumcoromandelianum leaves. The extract was tested for antithelmintic activity against adult Indian earthworm and also tested for antibacterial activity against the gram positive bacteriaS.aureus,B.subtilis and gram negative bacteria against E.Coli, P.aerugenosa, P.putida.The anthelmintic activity was observed at 100mg/ml with reference to standardAlbendazole(10mg/ml).The maximum antibacterial activity was observed in S.aureus at 500mg/ml with of zone of inhibition17 mm and next is S.aureus, the best antibacterial activity was observed against P.aerugenosa and P.putidawith 15 mm of zone of inhibition. The zone of inhibition of extract was compared with standard Gentamycin 25 µg/ml. The extract shows significant activity against the other bacterial pathogens. From the results, it was concluded that the ethanolic extract of Malvastrumcoromandelianum leaves have anthelmintic and antibacterial activity.

Estructura morfo-anatómica y salida de dormición física de las semillas de Malvastrum coromandelianum ssp. coromandelianum (Malvaceae)

Introducción y objetivos: Uno de los principales problemas para el manejo y uso de muchas especies vegetales es la presencia de semillas con dormición física. En este trabajo estudiamos la presencia de dormición física en mericarpos (unidad de dispersión) y semillas, las estructuras morfo-anatómicas involucradas y los métodos de salida de dormición física en semillas de Malvastrum coromandelianum (Malvaceae). M&M: Se realizaron ensayos de imbibición en mericarpos y en semillas intactas y escarificadas. Se describió la estructura morfo-anatómica de las semillas con microscopio electrónico de barrido y se evaluó el efecto de la escarificación mecánica, química y térmica sobre la germinación y estructura de las semillas. Resultados: Los mericarpos y las semillas escarificadas incrementaron > 160% su peso inicial, mientras que las semillas intactas incrementaron < 40% su peso. Las semillas presentaron una cubierta con células en empalizada y un complejo de abertura al agua ubicado en la región chalazal. Los mayores porcentajes y menores t 50 se registraron luego de la escarificación mecánica, seguido de la química y térmica (calor seco). Las escarificaciones química y térmica produjeron la eliminación de la tapa chalazal y formación de grietas alrededor de la región chalazal, mientras que la formación y eliminación de una ampolla chalazal sólo se observó luego de la escarificación química. Conclusiones: Las semillas de M. coromandelianum presentan dormición física. El ingreso de agua ocurre a través de un complejo de abertura (Tipo III compuesto) en la región chalazal de las semillas. Las escarificaciones mecánica, química y térmica son métodos eficientes para la salida de la dormición física y germinación de semillas.