Studies on drought tolerance in maize inbred lines using morphological and molecular approaches

A set of hundred homozygous maize inbred lines were analyzed for drought toleranceby studying twenty-four traits related to maturity, morphological, physiological, yield, quality and few root traits. Evaluation confirmed a wide range of variability revealing significant response of main effects (lines, irrigations and years and their respective digenic and trigenic interactions). These lines were subjected to different stress regimes over years leading to identification of fifteen elite lines which performed well under droughtstress showing inbuilt drought tolerance. A set of 32 SSR markers, having genome-wide coverage, were chosen for genotyping the inbred lines. These markers generated a total of 239 polymorphic alleles with an average of 7.47 alleles per locus. The minimum and maximum PIC value was 0.886 and 0.608 with a mean of 0.782. The coefficient of genetic dissimilarity ranged from 0.215 to 0.148. DARwin derived cluster analysis grouped 15 elite maize lines in three major clusters with five lines each in cluster-III and II and four lines in cluster-I with KDM-361A as root. Molecular diversity however, confirmed diverse genetic nature of six lines (KDM-372, KDM-343A, KDM-331, KDM-961, KDM-1051 and KDM-1156) showing drought tolerance. Exploitation of identified elite lines in a crossing program involving all possible combinations would help to develop hybrids with inbuilt mechanism to drought tolerance. Markers viz., umc -1766, umc-1478 and phi-061 recorded PIC >8 and alleles per locus more than 9 and therefore, discriminated the set of lines more efficiently. Genotyping data complemented by morpho- hysiological parameters were used to identify a number of pair-wise combinations for the development of mapping population segregating for drought tolerance and potential heterotic pairs for the development of drought tolerant hybrids.

Life style patterns and adherence to pharmacotherapy after acute coronary syndrome: one year follow up study from a tertiary care center in Kashmir, India

Background: Acute coronary syndrome is the leading cause of cardiac mortality and morbidity world over. Modification of life style pattern and adherence to pharmacotherapy plays a vital role in primary and secondary prevention of coronary events. This study was aimed at assessing the penetration of life style modifications and adherence to pharmacotherapy after acute coronary event in our population.Methods: Acute coronary syndrome patients enrolled in the study were examined, interviewed and all the demographic and clinical data was recorded at index event and at 3, 6 and 12 month intervals.Results: A total of 260 patients were enrolled in the study and followed for 12 months. Mean age of patients was 55.6±8.27 years. Males 78.6% and females 21.5%. Hypertension was risk factor in 67.7%, diabetes in 26.2%, smoking in 63.8%, BMI ≥25 in 67.3% and family history of coronary artery disease in 8.8% of the cases at index event. Uncontrolled hypertension was observed in 30.11%, 38.63% and 44.88% patients at 3, 6 and 12 months follow up. Uncontrolled diabetes at 3, 6 and 12 months was found in 58.82%, 66.17% and 73.52% patients. 5.42%, 15.06% and 21.08% cases continued to smoke at 3, 6 and 12 months respectively. Drug non-compliance overall was noted in 9.61%, 17.69% and 23.84% cases at 3, 6 and 12 month follow up.Conclusions: This study highlights the under prevalence of modifiable risk factor change in practice and drug non-compliance after an acute coronary event

Pathogenic variability in Exserohilum turcicum and identification of resistant sources to turcicum leaf blight of maize (Zea mays L.)

Turcicum leaf blight of maize incited by Exserohilum turcicum (Pass.) Leonard and Suggs is the major limiting factor of maize production in temperate agro-ecologies. Disease management through host plant resistance is the most effective strategy. In the present study among 26 maize genotypes which were initially screened for resistance against E. turcicum under field conditions, 8 genotypes viz., PS 39, CML 451, CML 470, CML 472, VL 1030, VL 1018140, VL1018527 and SMI178-1 were found resistant when screened against twelve isolates of E. turcicum under artificial epiphytotic conditions. Eight genotypes viz., PS45, CML165, CML459, VL1249, VL0536, SMC-5, SMC-3 and KDL 211 were found moderately resistant with disease grade ranged from 2.1-2.5. These maize genotypes possess resistance to turcicum leaf blight can be used successfully in developing high yielding early maturing varieties for high altitude temperate agro-ecologies. The fungus E. turcicum is highly variable in nature. Variability studies on pathogenicity were conducted on twelve isolates of E. turcicum on eleven putative differential maize lines. During the present study a wide pathogenic variation was observed among the twelve isolates of E. turcicum. Cluster analysis on the basis of similarity or dissimilarity in reaction types exhibited by the differential hosts, clustered the isolates into 6 pathogenic groups. The isolates belonged to higher altitudes (Kti 10, Kti11, Kti5) were found to be more aggressive as compared to the isolates of low altitude areas

Breeding strategies for improving growth and yield under waterlogging conditions in maize: A review

Waterlogging, caused by flooding, excessive rains and poor drainage is a serious abiotic stress determining crop productivity worldwide. Maize (Zea mays L) is a basic food grain in many areas and several cultures and is culti- vated under much diverse agro-climatic zones extending from subtropical to cooler temperate regions. Therefore, the crop remains open to varied types of biotic as well as abiotic stresses. Among various abiotic stresses, water- logging is one of the most important constraints for maize production and productivity. Breeding for improved wa- terlogging tolerance includes modification of plant morphology, use of tolerant secondary traits and development of resistant varieties through conventional breeding and biotechnological approaches. A successful programme in conventional breeding should involve the integration of several criteria into one selection index and also successful breeding programmes for improved tolerance to submergence stress frequently combine two or more breeding strategies. Marker assisted selection (MAS) is an effective approach to identify genomic regions of crops under stress and construction of molecular linkage maps enable carry out pyramiding of desirable traits to improve sub- mergence tolerance through MAS

Sweetpotato cultivars responses to interactive effects of warming, drought, and elevated carbon dioxide

Plants are sensitive to changes projected in climates, such as elevated carbon dioxide (eCO2), high temperature (T), and drought stress (DS), which affect crop growth, development, and yield. These stresses, either alone or in combination, affect all aspects of sweetpotato plant growth and development, including storage root development and yield. We tested three sweetpotato cultivars (Beauregard, Hatteras, and LA1188) responses to eight treatments (Control, DS, T, eCO2, DS + T, T + eCO2, DS + eCO2, DS + T + eCO2). All treatments were imposed 36 days after transplanting (DAP) and continued for 47 days. Treatments substantially affected gas exchange, photosynthetic pigments, growth, and storage root components. Cultivars differed considerably for many of the measured parameters. The most significant negative impact of DS was recorded for the shoot and root weights. The combination of DS + T had a significant negative effect on storage root parameters. eCO2 alleviated some of the damaging effects of DS and high T in sweetpotato. For instance, eCO2 alone or combined with DS increased the storage root weights by 22% or 42% across all three cultivars, respectively. Based on the stress response index, cultivar “Hatteras” was most tolerant to individual and interactive stresses, and “LA 1188” was sensitive. Our findings suggest that eCO2 negates the negative impact of T or DS on the growth and yield of sweetpotato. We identified a set of individual and interactive stress-tolerant traits that can help select stress cultivars or breed new lines for future environments

Liquid Biopsy: A Step Closer to Transform Diagnosis, Prognosis and Future of Cancer Treatments

Over the past decade, invasive techniques for diagnosing and monitoring cancers are slowly being replaced by non-invasive methods such as liquid biopsy. Liquid biopsies have drastically revolutionized the field of clinical oncology, offering ease in tumor sampling, continuous monitoring by repeated sampling, devising personalized therapeutic regimens, and screening for therapeutic resistance. Liquid biopsies consist of isolating tumor-derived entities like circulating tumor cells, circulating tumor DNA, tumor extracellular vesicles, etc., present in the body fluids of patients with cancer, followed by an analysis of genomic and proteomic data contained within them. Methods for isolation and analysis of liquid biopsies have rapidly evolved over the past few years as described in the review, thus providing greater details about tumor characteristics such as tumor progression, tumor staging, heterogeneity, gene mutations, and clonal evolution, etc. Liquid biopsies from cancer patients have opened up newer avenues in detection and continuous monitoring, treatment based on precision medicine, and screening of markers for therapeutic resistance. Though the technology of liquid biopsies is still evolving, its non-invasive nature promises to open new eras in clinical oncology. The purpose of this review is to provide an overview of the current methodologies involved in liquid biopsies and their application in isolating tumor markers for detection, prognosis, and monitoring cancer treatment outcomes

Breeding Maize for Food and Nutritional Security

Maize occupies an important position in the world economy, and serves as an important source of food and feed. Together with rice and wheat, it provides at least 30 percent of the food calories to more than 4.5 billion people in 94 developing countries. Maize production is constrained by a wide range of biotic and abiotic stresses that keep afflicting maize production and productivity causing serious yield losses which bring yield levels below the potential levels. New innovations and trends in the areas of genomics, bioinformatics, and phenomics are enabling breeders with innovative tools, resources and technologies to breed superior resilient cultivars having the ability to resist the vagaries of climate and insect pest attacks. Maize has high nutritional value but is deficient in two amino acids viz. Lysine and Tryptophan. The various micronutrients present in maize are not sufficient to meet the nutritive demands of consumers, however the development of maize hybrids and composites with modifying nutritive value have proven to be good to meet the demands of consumers. Quality protein maize (QPM) developed by breeders have higher concentrations of lysine and tryptophan as compared to normal maize. Genetic level improvement has resulted in significant genetic gain, leading to increase in maize yield mainly on farmer’s fields. Molecular tools when collaborated with conventional and traditional methodologies help in accelerating these improvement programs and are expected to enhance genetic gains and impact on marginal farmer’s field. Genomic tools enable genetic dissections of complex QTL traits and promote an understanding of the physiological basis of key agronomic and stress adaptive and resistance traits. Marker-aided selection and genome-wide selection schemes are being implemented to accelerate genetic gain relating to yield, resilience, and nutritional quality. Efforts are being done worldwide by plant breeders to develop hybrids and composites of maize with high nutritive value to feed the people in future

Reactive Oxygen Species, Oxidative Damage and Their Production, Detection in Common Bean (<em>Phaseolus vulgaris</em> L.) under Water Stress Conditions

Reactive oxygen species (ROS) being small and highly reactive oxygen containing molecules play significant role in intracellular signaling and regulation. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. This increased ROS production is, however, tightly controlled by a versatile and cooperative antioxidant system that modulates intracellular ROS concentration and controls the cell’s redox status. Furthermore, ROS enhancement under stress serves as an alarm signal, triggering acclimatory/defense responses via specific signal transduction pathways involving H2O2 as a secondary messenger. Nevertheless, if water stress is prolonged over to a certain extent, ROS production will overwhelm the scavenging action of the anti-oxidant system resulting in extensive cellular damage and death. DAB (3,3′-diaminobenzidine) test serves as an effective assessment of oxidative damage under stress. It clearly differentiates the lines on the basis of darker staining of leaves under water stress. The lines showing greater per cent reduction in yield parameters show greater staining in DAB assay underlining the reliability of using this assay as a reliable supplement to phenotyping protocols for characterizing large germplasm sets

Lymphoma Presenting as Severe Left Ventricular Systolic Dysfunction: A Case Report

Lymphoma involving the heart is rare. This is a case report on non-Hodgkin lymphoma where the patient presented for the first time with heart failure and severe left ventricular systolic dysfunction due to lymphoma infiltrating the heart muscle and had simultaneous bilateral involvement of kidneys. This type of presentation has never been described in world literature and is the first reported case

Drought Stress Tolerance Screening of Elite American Breeding Rice Genotypes Using Low-Cost Pre-Fabricated Mini-Hoop Modules

Drought is a major abiotic stress factor affecting the growth and development of plants at all stages. Developing a screening tool for identifying drought stress tolerance during seedling establishment is important in the deployment of rice varieties suited to water-limited growing environments. An experiment was conducted to evaluate 100 rice genotypes, mostly belonging to the tropical japonica subspecies, for drought stress tolerance using low-cost, pre-fabricated mini-hoop structures. The rice seedlings were subjected to two different soil moisture regimes- control pots managed at 100% and drought pots at 50% field capacity, from 12 to 30 days after sowing (DAS). Several morpho-physiological parameters including root traits were measured to assess the response of genotypes to drought stress. Significant moisture stress &#215; genotype interactions were found for most of the parameters measured. A cumulative drought stress response index (CDSRI) was developed by adding the individual response indices of all cultivars. Based on CDSRI and standard deviation values, 5 and 28 genotypes were identified as highly sensitive and sensitive to drought, respectively, and 45 as moderately sensitive. On the other hand, 16 and 6 genotypes were classified as tolerant and highly tolerant to drought, respectively. Cheniere, a released cultivar, and RU1402174, an experimental breeding line, were identified as the least and most tolerant to drought among the 100 genotypes tested. Significant linear correlation coefficients were obtained between CDSRI and root growth parameters (R2 = 0.91, n = 100) and CDSRI with shoot growth parameters (R2 = 0.48, n = 100), revealing the importance of root traits in studying and identifying drought tolerant lines during the seedling establishment stages in rice. The tolerant rice genotypes identified will be valuable for rice scientists in studying the mechanism for early season drought as well as for rice breeders for developing new genotypes best suited under growing environments prone to early-season drought