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Grass pea (Lathyrus sativus L.) is a worldwide popular pulse crop especially for its protein rich seeds with least production cost. However, the use of the crop became controversial due to the presence of non-protein amino acid, β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP) in its seed and leaf, which is known as the principle neurotoxin to cause neurolathyrism (a motor neurodegenerative disease of humans and animals) during prolonged consumption as regular diet. Till date, the knowledge on β-ODAP biosynthesis in Lathyrus sp. is limited only to a small part of the complex bio-chemical steps involved including a few known sulfur-containing enzymes (viz. cysteine synthase, ODAP synthase etc.). In Lathyrus sativus, biosynthesis of β-ODAP varies differentially in a tissue-specific manner as well as in response to several environmental stresses viz. zinc deficiency, iron over-exposure, moisture stress etc. In the present study, a novel cysteine synthase gene (LsCSase) from Lathyrus sativus L was identified and characterized through bioinformatics approaches. The bioinformatic analysis revealed that LsCSase showed maximum similarity with the O-acetyl serine (thiol) lyase of Medicago truncatula with respect to several significant sequence-specific conserved motifs (cysK, CBS like, ADH_zinc_N, PALP), sub-cellular localization (chloroplast or cytoplasm) etc., similar to other members of cysteine synthase protein family. Moreover, the tissue-specific regulation of the LsCSase as well as its transcriptional activation under certain previously reported stressed conditions (low Zn+2-high Fe+2, PEG induced osmotic stress) were also documented through quantitative real-time PCR analyses, suggesting a possible link between the LsCSase gene activation and β-ODAP biosynthesis to manage external stresses in grass pea. This preliminary study offers a probable way towards the development of less toxic consumer-safe grass pea by down-regulation or deactivation of such gene/s (cysteine synthase) through genetic manipulations.

To meet current challenges in agriculture, genome editing using sequence-specific nucleases (SSNs) is a powerful tool for basic and applied plant biology research. Here, we describe the principle and application of available genome editing tools, including zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and the clustered regularly interspaced short palindromic repeat associated CRISPR/Cas9 system. Among these SSNs, CRISPR/Cas9 is the most recently characterized and rapidly developing genome editing technology, and has been successfully utilized in a wide variety of organisms. This review specifically illustrates the power of CRISPR/Cas9 as a tool for plant genome engineering, and describes the strengths and weaknesses of the CRISPR/Cas9 technology compared to two well-established genome editing tools, ZFNs and TALENs.

Emergence of resistant insects limits the sustainability of Bacillus thuringiensis (Bt) transgenic crop plants for insect management. Beside this, the presence of unwanted marker gene(s) in the transgenic crops is also a major environmental and health concern. Thus, development of marker free transgenic crop plants expressing a new class of toxin having a different mortality mechanism is necessary for resistance management. In a previous study, we generated an engineered Cry2Aa (D42/K63F/K64P) toxin which has a different mortality mechanism as compared to first generation Bt toxin Cry1A, and this engineered toxin was found to enhance 4.1-6.6-fold toxicity against major lepidopteran insect pests of crop plants. In the present study, we have tested the potency of this engineered synthetic Cry2Aa (D42/K63F/K64P) toxin as a candidate in the development of insect resistant transgenic tobacco plants. Simultaneously, we have eliminated the selectable marker gene from the Cry2Aa (D42/K63F/K64P) expressing tobacco plants by exploiting the Cre/lox mediated recombination methodology, and successfully developed marker free T2 transgenic tobacco plants expressing the engineered Cry2Aa toxin. Realtime and western blot analysis demonstrated the expression of engineered toxin gene in transgenic plants. Insect feeding assays revealed that the marker free T2 progeny of transgenic plants expressing Cry2Aa (D42/K63F/K64P) toxin showed 82-92 and 52-61 % mortality to cotton leaf worm (CLW) and cotton bollworm (CBW) respectively. Thus, this engineered Cry2Aa toxin could be useful for the generation of insect resistant transgenic Bt lines which will protect the crop damages caused by different insect pests such as CLW and CBW.

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. Electronic supplementary material The online version of this article (doi:10.1186/s12870-016-0845-x) contains supplementary material, which is available to authorized users.