The sucrose non-fermenting 1-related kinase 2 gene SAPK9 improves drought tolerance and grain yield in rice by modulating cellular osmotic potential, stomatal closure and stress-responsive gene expression

Abstract Background Family members of sucrose non-fermenting 1-related kinase 2 (SnRK2), being plant-specific serine/threonine protein kinases, constitute the central core of abscisic acid (ABA)-dependent and ABA-independent signaling pathways, and are key regulators of abiotic stress adaptation in plants. We report here the functional characterization of SAPK9 gene, one of the 10 SnRK2s of rice, through developing gain-of-function and loss-of-function phenotypes by transgenesis. Results The gene expression profiling revealed that the abundance of single gene-derived SAPK9 transcript was significantly higher in drought-tolerant rice genotypes than the drought-sensitive ones, and its expression was comparatively greater in reproductive stage than the vegetative stage. The highest expression of SAPK9 gene in drought-tolerant Oryza rufipogon prompted us to clone and characterise the CDS of this allele in details. The SAPK9 transcript expression was found to be highest in leaf and upregulated during drought stress and ABA treatment. In silico homology modelling of SAPK9 with Arabidopsis OST1 protein showed the bilobal kinase fold structure of SAPK9, which upon bacterial expression was able to phosphorylate itself, histone III and OsbZIP23 as substrates in vitro. Transgenic overexpression (OE) of SAPK9 CDS from O. rufipogon in a drought-sensitive indica rice genotype exhibited significantly improved drought tolerance in comparison to transgenic silencing (RNAi) lines and non-transgenic (NT) plants. In contrast to RNAi and NT plants, the enhanced drought tolerance of OE lines was concurrently supported by the upgraded physiological indices with respect to water retention capacity, soluble sugar and proline content, stomatal closure, membrane stability, and cellular detoxification. Upregulated transcript expressions of six ABA-dependent stress-responsive genes and increased sensitivity to exogenous ABA of OE lines indicate that the SAPK9 is a positive regulator of ABA-mediated stress signaling pathways in rice. The yield-related traits of OE lines were augmented significantly, which resulted from the highest percentage of fertile pollens in OE lines when compared with RNAi and NT plants. Conclusion The present study establishes the functional role of SAPK9 as transactivating kinase and potential transcriptional activator in drought stress adaptation of rice plant. The SAPK9 gene has potential usefulness in transgenic breeding for improving drought tolerance and grain yield in crop plants.http://deepblue.lib.umich.edu/bitstream/2027.42/134605/1/12870_2016_Article_845.pd

Correction: Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: a practical route to imidazo[1,2-<i>a</i>]pyridine derivatives

Correction for ‘Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: a practical route to imidazo[1,2-a]pyridine’ by Surya Kanta Samanta et al., Org. Biomol. Chem., 2019, 17, 6441–6449.</p

Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: a practical route to imidazo[1,2-<i>a</i>]pyridine derivatives

A novel, transition-metal free route leading to imidazo[1,2-a]pyridine derivatives via iodine mediated oxidative coupling between 2-aminopyridine and aromatic terminal alkyne has been demonstrated.</p

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Not AvailableThe innate immunity serves as the first line of defence against invasion of pathogens in fish. Toll-like receptors (TLRs) play a pivotal role in the innate immunity by specific pathogen-associated molecules that activate immune responses. In the present study, analysis of TLR 20 and TLR 21 in different tissues of healthy catfish, Heteropneustes fossilis showed that the patterns of the gene expression were in the order of spleen > intestine > head kidney > gill and gill > head kidney > liver > spleen > intestine, respectively. Relative transcription of TLR 20 and TLR 21 in different tissues of the fish against bacterial infection investigated by semi- quantitative RT-PCR showed that expression of both TLR 20 and TLR 21 were up-regulated in spleen and intestine whereas that of TLR 21 expression was down-regulated in kidney, gill and liver relative to control fish. Findings of the study suggested that spleen and intestine showed significant alteration in both TLR 20 and TLR 21 expression. Expression of TLR 21 found to be more sensitive than TLR 20 against bacterial infection in fish.ICAR-NAI