ABSTRACT
Aims@#Sheath blight disease (Rhizoctonia solani) is an important rice disease that causes heavy yield losses in rice annually. To date, no rice variety has been found to be completely resistant to this disease. The most desirable approach for the management of sheath blight disease is to introgress genes with major and durable resistance into the rice genome. Therefore, this study aims to identify disease resistance and defence genes within qShb 9-2, a major QTL found within moderately resistant rice population via in silico analysis. @*Methodology and results@#The sequences of tightly linked markers of qShb 9-2 from GRAMENE database was used to derive the 10.24 Mbp QTL region that contains 1581 genes according to MSU Rice Genome Annotation Project database. BLAST results showed that 11.4% of these genes were transposable elements which may be involved in gene duplication. Through Blast2GO, fifty-four (2.9%) defence-related genes were annotated within this QTL and can be classified into 5 major defence mechanisms. Further, fifty (2.7%) disease resistance genes were identified in qShb 9-2 based on the presence of NB-ARC, LRR-receptor kinase, Ser/Thr protein kinase and protein kinase domains. Lastly, directed acyclic graphs showing the interaction between all the disease resistance and defence-related genes were generated. @*Conclusion, significance and impact of study@#The presence of these genes indicates that qShb 9-2 region may contribute towards the defence against sheath blight disease. By deciphering the gene landscape within the QTL, it may be possible to further fine map the QTL into a smaller region for QTL pyramiding in breeding programmes. The resistance and defence genes are also a source for genetic engineering studies and a good source for marker development.
ABSTRACT
Aims@#Rice blast, a disease caused by the fungus Magnaporthe grisea is one of the serious diseases of rice in the world. The main objective of this study is to isolate and characterise the proteins extracted from the rice blast fungus, M. grisea 7.6. @*Methodology and results@#Through comparative 2-D analyses of the crude protein extracts obtained from this fungus, we were able to identify 88 protein spots through MALDI-TOF. These proteins were then classified into 8 functional groups through the Pfam and KEGG databases into hypothetical, transferases, energy and carbon metabolism, oxidoreductases, molecular chaperone, hydrolases, structural organisation and kinases. The individual protein’s functions were then identified and their possible role in pathogenesis, virulence and proliferation of M. grisea 7.6 were predicted. @*Conclusion, significance and impact of study@#Through the assays conducted, we were able to identify some proteins and pathways that could be targeted in developing fungicides and used in future mutagenesis studies.
ABSTRACT
Abstract@#Transmission of extracellular signal across the plasma membrane into the cells of organisms is impossible without cell surface receptors. One of the most broadly studied receptor is the G-protein coupled receptor. This receptor is coupled with heterotrimeric G proteins with α, β and γ subunits that perceives external stimuli and transduces the signal into the cell for suitable physiological and biochemical responses. They have also been reported as potential receptors to sense light and fatty acids, but their exact mechanism remains unclear in fungi. Signalling and regulation via G proteins has been extensively studied in various models including pathogenic fungi. Fungal GPCRs are broadly required in fungal defence stimulation, vegetative growth, and pathogenicity mechanism. This review aims to highlight the research in fungal GPCRs including classification, physiological roles, mechanisms of action and signalling in GPCR function. Through fungal genome sequencing, mammalian GPCRs have been identified apart from fungal-specific GPCRs which adds another dimension to the classification. The deorphanisation of unclassified fungal GPCRs is necessary to further understand their role in fungi. While the mechanism of action has been well documented in mammals, the glucose and pheromone sensing are the only two well mapped systems in yeast. However, we are yet to ascertain if there are any additional mechanisms of signalling at work in fungi. Further we endeavour to compare and contrast between the eukaryotic GPCRs in various aspects of functionality. Through the information derived we hope to determine the gaps in knowledge and by so doing determine the future directions of GPCR research in fungi.