Farmers occasionally need to add nitrogen fertilizer to their farms and gardens to make available just the precise nutrients for their plants' growth. The applications of inorganic nitrogen fertilizers to various crops have been continuously increasing since last many decades globally. Although nitrogen fertilizer contributes substantially to yield enhancement, but excessive use of this manure has posed serious threats to environment and human health. Rate of nitrogen fertilizers application has a close relationship with nitrate accumulation in surrounding environment, groundwater, as well as leafy and root vegetables. Consumption of diets having high nitrate contents has contributed to endogenous nitrosation, which could lead to thyroid condition, various kinds of human cancers, neural tube defects (during fetus development), and diabetes. In this short review, the authors have tried to create awareness among general public, farming community, health practitioners, and agricultural scientists for the risk involved with excessive use of nitrogen fertilizers to human health. Carcinogenic activity and other adverse effects of N-nitroso compounds might be prevented by consuming vitamin C and antioxidants containing fruits and vegetables.

Many of the toxin proteins, that have been heterogeneously expressed in agricultural crops to provide resistance to insect pests, are too specific or are only mildly effective against the major insect pests. Spider venoms are a complex cocktail of toxins that have evolved specifically to kill insects. Here we show that the omega-ACTX-Hv1a toxin (Hvt), a component of the venom of the Australian funnel web spider (Hadronyche versuta) that is a calcium channel antagonist, retains its biological activity when expressed in a heterologous system. Expressed as a fusion protein in E. coli, the purified toxin fusion immobilized and killed Helicoverpa armigera and Spodoptera littoralis caterpillars when applied topically. Transgenic expression of Hvt in tobacco effectively protected the plants from H. armigera and S. littoralis larvae, with 100% mortality within 48 h. We conclude that the Hvt is an attractive and effective molecule for the transgenic protection of plants from herbivorous insects which should be evaluated further for possible application in agriculture.

A silicon carbide whisker-mediated gene transfer system with recovery of fertile and stable transformants was developed for cotton (Gossypium hirsutum L.) cv. Coker-312. Two-month-old hypocotyl-derived embryogenic/non-embryogenic calli at different days after subculture were treated with silicon carbide whiskers for 2 min in order to deliver pGreen0029 encoding GUS gene and pRG229 AVP1 gene, encoding Arabidopsis vacuolar pyrophosphatase, having neomycin phosphotransferaseII (nptII) genes as plant-selectable markers. Three crucial transformation parameters, i.e., callus type, days after subculture and selection marker concentration for transformation of cotton calli were evaluated for optimum efficiency of cotton embryogenic callus transformation giving upto 94% transformation efficiency. Within six weeks, emergence of kanamycin-resistant (kmr) callus colonies was noted on selection medium. GUS and Southern blot analysis showed expression of intact and multiple transgene copies in the transformed tissues. Kanamycin wiping of leaves from T1, T2, and T3 progeny plants revealed that transgenes were inherited in a Mendelian fashion. Salt treatment of T1 AVP1 transgenic cotton plants showed significant enhancement in salt tolerance as compared to control plants. Thus far, this is first viable physical procedure after particle bombardment available for cotton that successfully can be used to generate fertile cotton transformants.

Basmati rice is famous around the world for its flavor, aroma, and long grain. Its demand is increasing worldwide, especially in Asia. However, its production is threatened by various problems faced in the fields, resulting in major crop losses. One of the major problems is bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). Xoo hijacks the host machinery by activating the susceptibility genes (OsSWEET family genes), using its endogenous transcription activator like effectors (TALEs). TALEs have effector binding elements (EBEs) in the promoter region of the OsSWEET genes. Out of six well-known TALEs found to have EBEs in Clade III SWEET genes, four are present in OsSWEET14 gene's promoter region. Thus, targeting the promoter of OsSWEET14 is very important for creating broad-spectrum resistance. To engineer resistance against bacterial blight, we established CRISPR-Cas9 mediated genome editing in Super Basmati rice by targeting 4 EBEs present in the promoter of OsSWEET14. We were able to obtain four different Super Basmati lines (SB-E1, SB-E2, SB-E3, and SB-E4) having edited EBEs of three TALEs (AvrXa7, PthXo3, and TalF). The edited lines were then evaluated in triplicate for resistance against bacterial blight by choosing one of the locally isolated virulent Xoo strains with AvrXa7 and infecting Super Basmati. The lines with deletions in EBE of AvrXa7 showed resistance against the Xoo strain. Thus, it was confirmed that edited EBEs provide resistance against their respective TALEs present in Xoo strains. In this study up to 9% editing efficiency was obtained. Our findings showed that CRISPR-Cas9 can be harnessed to generate resistance against bacterial blight in indigenous varieties, against locally prevalent Xoo strains.