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Plant NADPH oxidases are key regulators of plant–microbe interactions and reactive oxygen species (ROS) are essential to plant defences against pathogens. A significant part in the role played by ROS has been ascribed to plant respiratory burst oxidase homologs (RBOHs). In potato ( Solanum tuberosum ), where RBOHs were previously shown to be involved in wound-induced oxidative burst, we assessed their expression after inoculation with Verticillium dahliae Kleb. and showed that StRbohA was the only homolog to be differentially induced in potato in response to inoculation. In order to investigate the potential role of this gene in plant protection against wilt diseases, we used Agrobacterium -mediated transformation of Arabidopsis to assess the effects of its overexpression on plant responses to V. dahliae . After inoculation with this pathogen, the transformed Arabidopsis line overexpressing StRbohA showed lower disease severity (percent damaged leaf area and vascular discoloration) as compared to the wild type. It also had higher ROS production and more cell death caused by hydrogen peroxide (H 2 O 2 ), compared to the wild type. Suberization of root cells was also more pronounced in the line overexpressing StRbohA , and supports a possible role for StRBOHA in plant resistance to V. dahliae . Together, these findings indicate that overexpressed StRbohA in Arabidopsis enhances the ROS-mediated defence mechanisms against V . dahliae and can be a potential tool to improve plant resistance to this and other soilborne pathogens that cause wilts in economically important crops. [ABSTRACT FROM AUTHOR]

Citrus greening or Huanglongbing (HLB) is one of the most severe diseases of citrus worldwide and no cure is available at present. Currently molecular techniques based on polymerase chain reaction (PCR) are mainly used for the identification of HLB disease. The aim of this study was to identify the causal pathogen of citrus greening disease in Bangladesh. A total of eight mandarin orange leaf samples from three citrus growing areas viz. Moulvibazar, Sylhet and Khagrachari were collected on the basis of visual investigation demonstrating blotchy mottle symptoms. The genomic DNA was extracted from midribs of each leaf sample and subjected to the PCR. Species specific primers A2/J5 was used to amplify a partial sequence of β-operon (rpl KAJL- rpo BC operon) of ribosomal protein gene. An amplicon size of 703 bp specific to the Candidatus Liberibacter asiaticus confirmed its presence. BLAST homology search with the sequenced data showed 99% identity with the sequence database of Candidatus Liberibacter asiaticus deposited in GenBank. These results confirmed the prevalence of Candidatus Liberibacter asiaticus causing citrus greening in Bangladesh. • Citrus greening disease was identified. • Genomic DNA was extracted from midribs of each leaf sample. • A partial sequence of β-operon (rpl KAJL- rpo BC operon) of ribosomal protein gene was detected. • An amplicon size of 703 bp specific to the Candidatus Liberibacter asiaticus (Las) confirmed its presence. • BLAST homology search with the sequenced data showed 99% identity with sequences of the Las deposited in GenBank. [ABSTRACT FROM AUTHOR]