Tailoring crops with superior product quality through genome editing: an update.

MAIN CONCLUSION: In this review, using genome editing, the quality trait alterations in important crops have been discussed, along with the challenges encountered to maintain the crop products' quality. The delivery of economic produce with superior quality is as important as high yield since it dictates consumer's acceptance and end use. Improving product quality of various agricultural and horticultural crops is one of the important targets of plant breeders across the globe. Significant achievements have been made in various crops using conventional plant breeding approaches, albeit, at a slower rate. To keep pace with ever-changing consumer tastes and preferences and industry demands, such efforts must be supplemented with biotechnological tools. Fortunately, many of the quality attributes are resultant of well-understood biochemical pathways with characterized genes encoding enzymes at each step. Targeted mutagenesis and transgene transfer have been instrumental in bringing out desired qualitative changes in crops but have suffered from various pitfalls. Genome editing, a technique for methodical and site-specific modification of genes, has revolutionized trait manipulation. With the evolution of versatile and cost effective CRISPR/Cas9 system, genome editing has gained significant traction and is being applied in several crops. The availability of whole genome sequences with the advent of next generation sequencing (NGS) technologies further enhanced the precision of these techniques. CRISPR/Cas9 system has also been utilized for desirable modifications in quality attributes of various crops such as rice, wheat, maize, barley, potato, tomato, etc. The present review summarizes salient findings and achievements of application of genome editing for improving product quality in various crops coupled with pointers for future research endeavors.

SSTP1, a Host Defense Peptide, Exploits the Immunomodulatory IL6 Pathway to Induce Apoptosis in Cancer Cells.

While the immunomodulatory pathways initiated in immune cells contribute to therapeutic response, their activation in cancer cells play a role in cancer progression. Also, many of the aberrantly expressed immunomodulators on cancer cells are considered as therapeutic targets. Here, we introduce host defense peptide (HDP), a known immuomodulator, as a therapeutic agent to target them. The cationic host defense peptides (HDPs), an integral part of the innate immune system, possess membranolytic activity, which imparts antimicrobial and antitumor efficacy to it. They act as immunomodulators by activating the immune cells. Though their antimicrobial function has been recently reassigned to immunoregulation, their antitumor activity is still attributed to its membranolytic activity. This membrane pore formation ability, which is proportional to the concentration of the peptide, also leads to side effects like hemolysis, limiting their therapeutic application. So, despite the identification of a variety of anticancer HDPs, their clinical utility is limited. Though HDPs are shown to exert the immunomodulatory activity through specific membrane targets on immune cells, their targets on cancer cells are unknown. We show that SSTP1, a novel HDP identified by shotgun cloning, binds to the active IL6/IL6Rα/gp130 complex on cancer cells, rearranging the active site residues. In contrast to the IL6 blockers inhibiting JAK/STAT activity, SSTP1 shifts the proliferative IL6/JAK/STAT signaling to the apoptotic IL6/JNK/AP1 pathway. In IL6Rα-overexpressing cancer cells, SSTP1 induces apoptosis at low concentration through JNK pathway, without causing significant membrane disruption. We highlight the importance of immunomodulatory pathways in cancer apoptosis, apart from its established role in immune cell regulation and cancer cell proliferation. Our study suggests that identification of the membrane targets for the promising anticancer HDPs might lead to the identification of new drugs for targeted therapy.

Differential response of Indian mustard (Brassica juncea L., Czern and Coss) under salinity: photosynthetic traits and gene expression.

To explore the effect of salt stress on photosynthetic traits and gene expression in Indian mustard, four genotypes CS 54 (national check for salinity), CS 52-SPS-1-2012 (salt tolerant mutant), CS 614-4-1-4-100-13 (salt sensitive mutant) and Pusa bold (high yielding variety) were evaluated under irrigation water salinity (ECiw 12, and 15 dS m-1). Results suggest genotype CS 52-SPS-1-2012 followed by CS 54 performed better under imposed salt stress due to differential regulation of Na+ accumulation in the roots and main stem, restriction of Na+ influx from root to shoot, maintaining higher net photosynthetic traits under saline stress compared to CS 614-4-1-4-100-13 and Pusa bold. Further, overexpression of antiporters (SOS1, SOS2, SOS3, ENH1 and NHX1) and antioxidant (APX1, APX4, DHAR1 and MDHAR) genes in salt tolerant genotypes CS 52-SPS-1-2012 and CS 54 demonstrated their significant role in imparting salt tolerance in Indian mustard.

Constitutive expression of Brassica juncea annexin, AnnBj2 confers salt tolerance and glucose and ABA insensitivity in mustard transgenic plants.

Annexins belong to a plasma membrane binding (in a calcium dependent manner), multi-gene family of proteins, which play ameliorating roles in biotic and abiotic stresses. The expression of annexin AnnBj2 of Indian mustard is tissue specific with higher expression in roots and under treatments with sodium chloride and abscisic acid (ABA) at seedling stage. The effect of constitutive expression of AnnBj2 in mustard was analyzed in detail. AnnBj2 OE (over expression) plants exhibited insensitivity to ABA, glucose and sodium chloride. The insensitivity/tolerance of the transgenic plants was associated with enhanced total chlorophylls, relative water content, proline, calcium and potassium with reduced thiobarbituric acid reactive substances and sodium ion accumulation. The altered ABA insensitivity of AnnBj2 OE lines is linked to downregulation of ABI4 and ABI5 transcription factors and upregulation of ABA catabolic gene CYP707A2. Furthermore, we found that overexpression of AnnBj2 upregulated the expression of ABA-dependent RAB18 and ABA-independent DREB2B stress marker genes suggesting that the tolerance phenotype exhibited by AnnBj2 OE lines is probably controlled by both ABA-dependent and -independent mechanisms.

Host Defense Peptides from Asian Frogs as Potential Clinical Therapies.

Host defense peptides (HDPs) are currently major focal points of medical research as infectious microbes are gaining resistance to existing drugs. They are effective against multi-drug resistant pathogens due to their unique primary target, biological membranes, and their peculiar mode of action. Even though HDPs from 60 Asian frog species belonging to 15 genera have been characterized, research into these peptides is at a very early stage. The purpose of this review is to showcase the status of peptide research in Asia. Here we provide a summary of HDPs from Asian frogs.