Muhammad Nasir Subhani

Silicon mediated biochemical changes in wheat under salinized and non-salinzed solution cultures

Silicon (Si) can alleviate salinity damage, a major threat to agriculture that causes instability in wheat production. We report on the effects of silicon (150 mg L -1 ) on the morphological, physiological and biochemical traits in wheat ( Triticum aestivum L.) cultivars (salt sensitive; Auqab-2000 and salt tolerant; SARC-5) differing in salt tolerance under saline (10 dS m -1 ) and non-saline (2 dS m -1 ) hydroponic culture. Silicon supplementation into the solution culture improved wheat growth and K + :Na + with reduced Na + and increased K + uptake. Moreover, higher relative water content (RWC), increase in chlorophyll fractions and its ratios and stimulated activities of superoxide dismutase (SOD) and catalase (CAT) were observed. Nevertheless, the activity of peroxidase (POD) was reduced. We conclude that silicon inclusion into the growth medium is of assistance for wheat growth by maintaining plant water status, better K + :Na + , low electrolyte leakage and improved plant defense system adversely influenced by salt stress. SARC-5 showed better performance than Auqab-2000. Key words: Antioxidants, K + :Na + , silicon, salt stress, wheat growth.

Augmenting the salt tolerance in wheat (Triticum aestivum ) through exogenously applied silicon

Although silicon improves the salt tolerance in grasses, the mechanism involved is still ambiguous. Moreover in wheat, classified as Si-accumulator, silicon can alleviate the salt stress. Hence in this study, the effects of silicon using calcium silicate (150 mg/L) on the morphology, physiology and biochemistry of wheat genotypes (salt sensitive; Auqab-2000 and salt tolerant; SARC-5) differing in salt tolerance under saline (12 dS/m) and non-saline soil media (2 dS/m) were investigated. Silicon supplementation into the root medium significantly improved the K + and K + :Na + ratio, leaf water potential and stomatal conductance, but reduced the Na + . Plants harvested at maturity indicated a concomitant increase in number of tillers, number of grains per spike, grain and straw yield with Si application both under optimal and stressful conditions. The results suggest that Si application in soil medium is beneficial in profoundly affecting physiological phenomena and improving wheat growth under salt stress. Keywords: Wheat, salt stress, silicon, wheat growth, K + :Na + , water potential, stomatal conductance.

Biofortification of Wheat Cultivars to Combat Zinc Deficiency

Zinc (Zn) deficiency caused by inadequate dietary intake is a global nutritional problem, particularly in developing countries. Therefore, zinc biofortification of wheat and other cereal crops is being urgently addressed and highly prioritized as a research topic. A field study was planned to evaluate the influence of zinc application on grain yield, grain zinc content, and grain phytic acid concentrations of wheat cultivars, and the relationships between these parameters. Three wheat cultivars, C1 = Faisalabad-2008, C2 = Punjab-2011, and C3 = Millet-2011 were tested with five different methods of zinc application: T1 = control, T2 = seed priming, T3 = soil application, T4 = foliar application, and T5 = soil + foliar application. It was found that grain yield and grain zinc were positively correlated, whereas, grain phytic acid and grain zinc were significantly negatively correlated. Results also revealed that T5, T3, and T4 considerably increased grain yield; however, T2 only slightly enhanced grain yield. Grain zinc concentration increased from 33.1 and 33.7 mg kg−1 in T1 to 62.3 and 63.1 mg kg−1 in T5 in 2013–2014 and 2014–2015, respectively. In particular, T5 markedly decreased grain phytic acid content; however, maximum concentration was recorded in T1. Moreover, all the tested cultivars exhibited considerable variation in grain yield, grain zinc, and grain phytic acid content. In conclusion, T5 was found to be most suitable for both optimum grain yield and grain biofortification of wheat.

Evaluation of Antifungal Effect of Different Plant Extracts for the Management of Late Blight of Potato Caused by Phytophthorain festans (Mont.) de Bary

Abstract In protective disease management Neem (Azadrachta indica) leaf extract was the most effective followed by Garlic (Allium sativum) extract but Neem (Azadrachtaindica) oil was least effective on all the five varieties (Cardinal, Karoda, Rodio, Shanan and Siply Red). Most effective dose of Neem (Azadrachta indica) leaf extract and all other plant extracts was 3 % followed by 2 % and 1 % being least effective while7 days spray interval was most effective as compared to 14, 21 and 28 days. In curative disease management program Neem (Azadrachta indica) leaf extract @3 % was most effective followed by Garlic (Allium sativum) extract @3 % while euclyptus (Eucalyptusglobulus) leaf extarct @3% being least effective on all the five varieties (Cardinal, Karoda, Rodio, Shanan and Siply Red). Three consecutive sprays after disease appearance were most effective among all the tested plant extracts followed by 2 and 1 sprays.

Evidence of genetically diverse virulent mating types of Phytophthora capsici from Capsicum annum L.

Chili pepper (Capsicum annum L.) is an important economic crop that is severely destroyed by the filamentous oomycete Phytophthora capsici. Little is known about this pathogen in key chili pepper farms in Punjab province, Pakistan. We investigated the genetic diversity of P. capsici strains using standard taxonomic and molecular tools, and characterized their colony growth patterns as well as their disease severity on chili pepper plants under the greenhouse conditions. Phylogenetic analysis based on ribosomal DNA (rDNA), β-tubulin and translation elongation factor 1α loci revealed divergent evolution in the population structure of P. capsici isolates. The mean oospore diameter of mating type A1 isolates was greater than that of mating type A2 isolates. We provide first evidence of an uneven distribution of highly virulent mating type A1 and A2 of P. capsici that are insensitive to mefenoxam, pyrimorph, dimethomorph, and azoxystrobin fungicides, and represent a risk factor that could ease outpacing the current P. capsici management strategies.

Invasive Aspergillus terreus morphological transitions and immunoadaptations mediating antifungal resistance

Background and aims Aspergillus terreus Thom is a pathogen of public health and agricultural importance for its seamless abilities to expand its ecological niche. The aim of this study was holistically to investigate A. terreus morphological and immunoadaptations and their implication in antifungal resistance and proliferation during infection. Materials and methods In-depth unstructured mining of relevant peer-reviewed literature was performed for A. terreus morphological, immune, resistance, and genetic diversity based on the sequenced calmodulin-like gene. Results Accessory conidia and phialidic conidia produced by A. terreus confer discrete anti-fungal resistance that ensures survivability during therapies. Interestingly, by producing unique metabolites such as Asp–melanin and terretonin, A. terreus is capable of hijacking macrophages and scavenging iron, respectively. As such, A. terreus has established a rare mechanism to mitigate phagocytosis and swing the interaction dynamics in favor of its proliferation and survival in hosts. Conclusion It is further unraveled that besides A. terreus genetic diversity, morphological, biochemical, and immunologic adaptations associated with conidia germination and discharge of chemical signals during infection enable masking of the host defense as an integral part of its strategy to survive and rapidly colonize hosts.