A Single-Tube, Functional Marker-Based Multiplex PCR Assay for Simultaneous Detection of Major Bacterial Blight Resistance Genes Xa21, xa13 and xa5 in Rice

AbstractIn marker-assisted breeding for bacterial blight (BB) resistance in rice, three major resistance genes, viz., Xa21, xa13 and xa5, are routinely deployed either singly or in combinations. As efficient and functional markers are yet to be developed for xa13 and xa5, we have developed simple PCR-based functional markers for both the genes. For xa13, we designed a functional PCR-based marker, xa13-prom targeting the InDel polymorphism in the promoter of candidate gene Os8N3 located on chromosome 8 of rice. With respect to xa5, a multiplex-PCR based functional marker system, named xa5FM, consisting of two sets of primer pairs targeting the 2-bp functional nucleotide polymorphism in the exon II of the gene TFIIAɤ5 (candidate for xa5), has been developed. Both xa13-prom and xa5FM can differentiate the resistant and susceptible alleles for xa13 and xa5, respectively, in a co-dominant fashion. Using these two functional markers along with the already reported functional PCR-based marker for Xa21 (pTA248), we designed a single-tube multiplex PCR based assay for simultaneous detection of all the three major resistance genes and demonstrated the utility of the multiplex marker system in a segregating population

A global research priority agenda to advance public health responses to fatty liver disease

Background & aims An estimated 38% of adults worldwide have non-alcoholic fatty liver disease (NAFLD). From individual impacts to widespread public health and economic consequences, the implications of this disease are profound. This study aimed to develop an aligned, prioritised fatty liver disease research agenda for the global health community. Methods Nine co-chairs drafted initial research priorities, subsequently reviewed by 40 core authors and debated during a three-day in-person meeting. Following a Delphi methodology, over two rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the priorities, via Qualtrics XM, indicating agreement using a four-point Likert-scale and providing written feedback. The core group revised the draft priorities between rounds. In R2, panellists also ranked the priorities within six domains: epidemiology, models of care, treatment and care, education and awareness, patient and community perspectives, and leadership and public health policy. Results The consensus-built fatty liver disease research agenda encompasses 28 priorities. The mean percentage of ‘agree’ responses increased from 78.3 in R1 to 81.1 in R2. Five priorities received unanimous combined agreement (‘agree’ + ‘somewhat agree’); the remaining 23 priorities had >90% combined agreement. While all but one of the priorities exhibited at least a super-majority of agreement (>66.7% ‘agree’), 13 priorities had 90% combined agreement. Conclusions Adopting this multidisciplinary consensus-built research priorities agenda can deliver a step-change in addressing fatty liver disease, mitigating against its individual and societal harms and proactively altering its natural history through prevention, identification, treatment, and care. This agenda should catalyse the global health community’s efforts to advance and accelerate responses to this widespread and fast-growing public health threat. Impact and implications An estimated 38% of adults and 13% of children and adolescents worldwide have fatty liver disease, making it the most prevalent liver disease in history. Despite substantial scientific progress in the past three decades, the burden continues to grow, with an urgent need to advance understanding of how to prevent, manage, and treat the disease. Through a global consensus process, a multidisciplinary group agreed on 28 research priorities covering a broad range of themes, from disease burden, treatment, and health system responses to awareness and policy. The findings have relevance for clinical and non-clinical researchers as well as funders working on fatty liver disease and non-communicable diseases more broadly, setting out a prioritised, ranked research agenda for turning the tide on this fast-growing public health threat

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

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Not AvailableGenetically modified crops are one of the prudent options for enhancing the production and productivity of crop plants by safeguarding from the losses due to biotic and abiotic stresses. Agrobacterium-mediated and biolistic transformation methods are used to develop transgenic crop plants in which selectable marker genes (SMG) are generally deployed to identify ‘true’ transformants. The commonly used SMG obtained from prokaryotic sources when employed in transgenic plants pose risks due to their lethal nature during selection process. In the recent past, some non-lethal SMGs have been identified and used for selection of transformants with increased precision and high selection efficiency. Considering the concerns related to bio-safety of the environment, it is desirable to remove the SMG in order to maximize the commercial success through wide adoption and public acceptance of genetically modified (GM) food crops. In this review, we examine the availability, and the suitability of wide range of non-lethal selection markers and elimination of SMG methods to develop marker-free transgenics for achieving global food security. As the strategies for marker-free plants are still in proof-of-concept stage, adaptation of new genomics tools for identification of novel non-lethal marker systems and its application for developing marker-free transgenics would further strengthen the crop improvement program.Department of Biotechnology, Govt. of Indi

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Not AvailableRice is the staple food for more than half of the world’s population. Demand for rice continues to increase due to the ever-increasing rice consumer base. However, the present rate of increase in rice production (2000-09) has slowed down (1.21%) compared with that of previous decades (1970-90, 2.49%; 1990- 2000, 1.70%) due to various biotic and abiotic stresses (Khush and Jena 2009). Among the biotic stresses, blast, a disease caused by Magnaporthe oryzae, is the most devastating, leading to a 90% yield loss in rice. Although many resistant varieties have already been bred, the breakdown of blast resistance causes yield instability in several rice-growing areas in the world. Of the various strategies tried, enhancement of host-plant resistance is considered one of the important approaches to tackle this disease. Pyramiding of two or more effective resistance genes/alleles into elite cultivars enhances the durability and spectrum of resistance. Hence, identifying superior alleles of effective resistance genes can be immensely helpful in increasing the degree of resistance and can be valuable in breeding durable resistance for blast disease (Ramkumar et al 2010). Of the various blast resistance genes characterized, Pikh and Pita are the two major genes found to confer broad-spectrum resistance to blast in India. With the identification and molecular characterization of Pikh (Madhav et al 2005) and Pita genes (Bryan et al 2000), it is now possible to dissect the naturally occurring allelic variation in these genes from a wide range of germplasm through allele mining. In our study, we used a sequence-based allele mining strategy to isolate novel resistance alleles of Pikh and Pita from landraces and wild Oryza species and studied their effectiveness against blastNot Availabl