Identification and Characterization of Salinity Tolerance Genes by Activation Tagging in Arabidopsis

Salinity often affects irrigated areas in arid and semi-arid regions of the world. The existence and accumulation of soluble salts in the soil layers limit the growth of crops essential for our food. Salt stress dramatically affects plant growth, plant development, as well as crop yield. Arabidopsis thaliana is the plant model that provides a comprehensive knowledge of plant development, genetics and physiology, and response to abiotic stresses such as salinity. The redundancy of genes due to duplication, even in the simple model genome of Arabidopsis, limits the value of knockout (KO) mutagenesis to provide complete information on gene function. ‘Gain-of-function’ mutants are an alternative genetic tool to identify gene functions for redundant genes, and those with small effect or that respond to an environmental condition. Transposon-mediated ‘activation tagging’ is an efficient genetic tool that can randomly generate ‘gain-of-function’ mutants for a large number of genes. In the method used here, the transposable element Enhancer-Inhibitor (En-I/dSpm) system of maize was modified to develop an activation tag (AT) mutant library in Arabidopsis. The mobile I-AT transposon contains a transcriptional enhancer, from the cauliflower mosaic virus (CaMV) 35S promoter, located close to the right border of the transposon. This I-AT element was mobilized to randomly insert into the plant genome by transposition from the T-DNA, and can give rise to mutants differing in the level of overexpression of the adjacent genes. Consequently, the gain-of-function dominant phenotypes generated are displayed by the I-AT plants due to enhanced expression of the gene(s) adjacent to the 35S enhancer. In this study, the I-AT library was used to screen for salt tolerance, identified by enhanced growth or biomass of the tagged mutants compared to the wild-type grown in saline conditions. A number of tagged salt tolerance candidate genes were identified flanking the I-AT insertion, and their tagged genes characterized for their role in salt tolerance

Development of Single Nucleotide Polymorphism (SNP) Markers in Tropical Crops

Understanding genetic diversity, association studies, evolution analysis, quantitative trait loci, marker-assisted selection and genome-wide association in tropical crops are important for improving plant characteristics in order to increase food sustainability in tropical countries. Single nucleotide polymorphism (SNP) marker is becoming the most popular molecular marker for those studies. By using SNP marker, genes associated with important traits can be identified efficiently compared to the other molecular markers. This review describes about how SNP can be discovered in the plant genomes and the application of SNP in plant breeding, especially in tropical crops such as rice, maize, peas, potato, tomato, cassava, taro, etc.   Keywords: food sustainability, plant breeding, SNP marker, tropical crop

Glycemic Index of Diverse Rice Genotypes and Rice Products Associated with Health and Diseases

Rice (Oryza sativa L.) is the primary source of carbohydrate for more than half of global population. The highest rice consumption is in Asia which more than 100 kg per capita. It has been reported that rice elicits a high glycemic index (GI) ranged from 54 to 121 which considers to the higher GI compared to other starchy foods. Rice consumption showed a positive correlation with diabetes incidences. Regular consumption of high-GI rice has been accelerating the development of type-II diabetes problem due to high blood glucose excursions and related to insulin resistance. The objective of this review is to identify rice genotypes and also the rice products for low GI which potentially provide information associated with good eating habits and prevent type-II diabetes and others related diseases. Information regarding GI value of rice and other rice products might help rice consumers to choose the right food to reduce the risk of health problems. Nowadays, it is difficult to find food products with nutritional label of GI value. Most of the food products, the GI value has not been defined yet. Determination of GI in food products will significantly support healthy eating habits

Efficacy of self-designed intraoral appliances in prevention of cheek, lip and tongue bite after local anesthesia administration in pediatric patients

The occurrence of self-inflicted soft tissue injuries following administration of local anesthesia in pediatric patients who have received dental treatment has been reported. Aim: To evaluate the attitudes and knowledge regarding cheek, lip, and tongue bite post administration of local anesthesia among dental practitioners in Saudi Arabia. Additionally, the efficacies of three types of intraoral appliances on the prevention of self-harm were evaluated in pediatric patients. A total of 301 practitioners were provided with a questionnaire consisting of 9 items. In addition, three types of intraoral appliances made of polyethylene terephthalate were designed as follows: design 1 (consisted of an anterior extension with numerous perforations); design 2 (had a buccal flap extension); and design 3 (comprised of serrated borders). The appliances were placed in the oral cavities of 45 children (age, 3?15 years) immediately after the completion of the dental procedure. The patient was asked to retain the appliance for 3 h. After 24 h, both parents and children were required to respond to a checklist to evaluate the effectiveness the appliances. Almost half of the dental practitioners had never encountered self-inflicted soft tissue injury in children after local anesthesia administration. About 60% of the dentists were of the opinion that provision of adequate instructions after treatment could prevent the occurrence of lip, cheek, and tongue biting. Furthermore, among the three appliances used, design 1 was most well accepted. Intraoral appliances used in this study may be considered for use to prevent self-inflicted soft tissue trauma in children following administration of local anesthesia

Exogenous application of moringa leaf extract improves growth, biochemical attributes, and productivity of late-sown quinoa

Quinoa (Chenopodium quinoa Willd.) has gained significant popularity among agricultural scientists and farmers throughout the world due to its high nutritive value. It is cultivated under a range of soil and climatic conditions; however, late sowing adversely affects its productivity and yield due to shorter growth period. Inorganic and organic phyto-stimulants are promising for improving growth, development, and yield of field crops under stressful environments. Field experiments were conducted during crop cultivation seasons of 2016–17 and 2017–18, to explore the role of inorganic (hydrogen peroxide and ascorbic acid) and organic [moringa leaf extract (MLE) and sorghum water extract (sorgaab)] phyto-stimulants in improving growth and productivity of quinoa (cultivar UAF-Q7). Hydrogen peroxide at 100 μM, ascorbic acid at 500 μM, MLE at 3% and sorgaab at 3% were exogenously applied at anthesis stage of quinoa cultivated under normal (November 21st and 19th during 2016 and 2017) and late-sown (December 26th and 25th during 2016 and 2017) conditions. Application of inorganic and organic phyto-stimulants significantly improved biochemical, physiological, growth and yield attributes of quinoa under late sown conditions. The highest improvement in these traits was recorded for MLE. Application of MLE resulted in higher chlorophyll a and b contents, stomatal conductance, and sub-stomatal concentration of CO2 under normal and late-sowing. The highest improvement in soluble phenolics, anthocyanins, free amino acids and proline, and mineral elements in roots, shoot and grains were observed for MLE application. Growth attributes, including plant height, plant fresh weight and panicle length were significantly improved with MLE application as compared to the rest of the treatments. The highest 1000-grain weight and grain yield per plant were noted for MLE application under normal and late-sowing. These findings depict that MLE has extensive crop growth promoting potential through improving physiological and biochemical activities. Hence, MLE can be applied to improve growth and productivity of quinoa under normal and late-sown conditions

Impact of different levels of zinc and nitrogen on growth, productivity, and quality of aromatic rice cultivated under various irrigation regimes in two districts of Pakistan

Rice is a staple food for more than 50% of the global population and it is one of the most valuable cereal crops. To fulfill the dietary requirement of the ever-growing world population, an increase in per-unit production of rice is direly required. In Pakistan, it stands as the 2nd in consumption after wheat, which is a staple food. A huge gap is observed between yield potential and actual yield of the aromatic rice cultivars at a farmer-field level. The significant limitations responsible for this gap are shortage of irrigation water, inappropriate application of fertilizers, less plant population, deficiency of micronutrients, and improper and poor plant protection measures. A field study was planned to assess the yield response and quality attributes of aromatic rice to three levels of zinc (Zn) and nitrogen (N) under three irrigation regimes (8-, 12-, and 16-acre inches) in the Sheikhupura and Sargodha districts of Pakistan. Irrigation treatments significantly influenced the growth, yield, and quality attributes; however, maximum improvement was observed by the application of irrigation at 12-acre inches. Among the Zn treatments, application of Zn at 10 kg ha–1 was observed to be more responsive to improving the growth and quality parameters of aromatic rice crops. In the case of N treatments, application of N at 140 kg ha–1 produced the maximum total tillers, as well as productive tillers per hill, spikelets per panicle, leaf area index, leaf area duration, crop growth rate, total dry matter, harvest index, kernel length, kernel width, and 1,000-kernel weight. Application of N at 140 kg ha–1 not only improved the growth attributes but also increased the net assimilation rate, photosynthetically active radiation, and radiation use efficiency, with respect to total dry matter and kernel yield. The maximum percentage of normal kernels and minimum percentage of opaque, abortive, and chalky kernels were also recorded by application of N at 140 kg ha–1. The outcomes of current experiments depicted that application of irrigational water, zinc, and nitrogen at 12-acre inches, 10, and 140 kg ha–1, respectively, are responsible to achieve maximum resource utilization efficiency, along with increased yield and quality of rice

Genetics, Biochemistry and Biophysical Analysis of Anthocyanin in Rice (Oryza sativa L.)

Rice (Oryza sativa L.) is the primary staple food for half of the world population. It is generally classified based on the grain color into black, red, purple, brown, green, and white. These colored rice are determined by the composition and concentration of anthocyanin pigments in different layers of aleurone, pericarp, and seed coat. Anthocyanins are also accumulated in various tissues of the rice plants, mostly in the grain, but are also presents in leaves, leaf sheath, floral organ, and hull. The type and concentration of the anthocyanins in rice tissues are influenced by the cultivars and developmental stages. Anthocyanin-enriched rice is related to the health effects, including antioxidant, antibacterial, and anti-inflammation activities that potentially use as functional food ingredients, dietary supplements, and natural colorants. Structural and regulatory genes are involved in anthocyanin biosynthesis of rice. Various molecular biology techniques have been applied to improve productivity, nutritional contents, and market value of pigmented rice. This review focused on the genetics, biochemistry and biophysical analysis of anthocyanin in rice that will facilitate rice breeding program to develop new high-yield pigmented rice varieties.

Development of Single Nucleotide Polymorphism (SNP) Markers in Tropical Crops

Understanding genetic diversity, association studies, evolution analysis, quantitative trait loci, marker-assisted selection and genome-wide association in tropical crops are important for improving plant characteristics in order to increase food sustainability in tropical countries. Single nucleotide polymorphism (SNP) marker is becoming the most popular molecular marker for those studies. By using SNP marker, genes associated with important traits can be identified efficiently compared to the other molecular markers. This review describes about how SNP can be discovered in the plant genomes and the application of SNP in plant breeding, especially in tropical crops such as rice, maize, peas, potato, tomato, cassava, taro, etc

Identification of Genomic Regions Controlling Chalkiness and Grain Characteristics in a Recombinant Inbred Line Rice Population Based on High-Throughput SNP Markers

Rice (Oryza sativa L.) is the primary food for half of the global population. Recently, there has been increasing concern in the rice industry regarding the eating and milling quality of rice. This study was conducted to identify genetic information for grain characteristics using a recombinant inbred line (RIL) population from a japonica/indica cross based on high-throughput SNP markers and to provide a strategy for improving rice quality. The RIL population used was derived from a cross of “Kaybonnet (KBNT lpa)” and “ZHE733” named the K/Z RIL population, consisting of 198 lines. A total of 4133 SNP markers were used to identify quantitative trait loci (QTLs) with higher resolution and to identify more accurate candidate genes. The characteristics measured included grain length (GL), grain width (GW), grain length to width ratio (RGLW), hundred grain weight (HGW), and percent chalkiness (PC). QTL analysis was performed using QTL IciMapping software. Continuous distributions and transgressive segregations of all the traits were observed, suggesting that the traits were quantitatively inherited. A total of twenty-eight QTLs and ninety-two candidate genes related to rice grain characteristics were identified. This genetic information is important to develop rice varieties of high quality

Growth and dry matter partitioning response in cereal-legume intercropping under full and limited irrigation regimes

Abstract The dry matter partitioning is the product of the flow of assimilates from the source organs (leaves and stems) along the transport route to the storage organs (grains). A 2-year field experiment was conducted at the agronomy research farm of the University of Agriculture Peshawar, Pakistan during 2015–2016 (Y1) to 2016–2017 (Y2) having semiarid climate. Four summer crops, pearl millet (Pennisetum typhoidum L.), sorghum (Sorghum bicolor L.) and mungbean (Vigna radiata L.) and pigeonpea (Cajanus cajan L.) and four winter crops, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), fababean (Vicia faba) and rapeseed (Brassica napus) were grown under two irrigation regimes (full vs. limited irrigation) with the pattern of growing each crop either alone as sole crop or in combination of two crops in each intercropping system under both winter and summer seasons. The result showed that under full irrigated condition (no water stress), all crops had higher crop growth rate (CGR), leaf dry weight (LDW), stem dry weight (SDW), and spike/head dry weight (S/H/PDW) at both anthesis and physiological maturity (PM) than limited irrigated condition (water stress). In winter crops, both wheat and barley grown as sole crop or intercropped with fababean produced maximum CGR, LDW, SDW, S/H/PDW than other intercrops. Among summer crops, sorghum intercropped either with pigeon pea or with mungbean produced maximum CGR, LDW, SDW, and S/H/PDW at both growth stages. Sole mungbean and pigeon pea or pigeon pea and mungbean intercropping had higher CGR, LDW, SDW, S/H/PDW than millet and sorghum intercropping. On the other hand, wheat and barley grown as sole crops or intercropped with fababean produced maximum CGR, LDW, SDW, and S/H/PDW than other intercrops. Fababean grown as sole crop or intercropped with wheat produced higher CGR, LDW, SDW, and S/H/PDW at PM than intercropped with barley or rapeseed. From the results it was concluded that cereal plus legume intercropping particularly wheat/fababean in winter and sorghum/pigeon pea or sorgum/mungbean in summer are the most productive intercropping systems under both low and high moisture regimes