Coping with drought: stress and adaptive mechanisms, and management through cultural and molecular alternatives in cotton as vital constituents for plant stress resilience and fitness

Increased levels of greenhouse gases in the atmosphere and associated climatic variability is primarily responsible for inducing heat waves, flooding and drought stress. Among these, water scarcity is a major limitation to crop productivity. Water stress can severely reduce crop yield and both the severity and duration of the stress are critical. Water availability is a key driver for sustainable cotton production and its limitations can adversely affect physiological and biochemical processes of plants, leading towards lint yield reduction. Adaptation of crop husbandry techniques suitable for cotton crop requires a sound understanding of environmental factors, influencing cotton lint yield and fiber quality. Various defense mechanisms e.g. maintenance of membrane stability, carbon fixation rate, hormone regulation, generation of antioxidants and induction of stress proteins have been found play a vital role in plant survival under moisture stress. Plant molecular breeding plays a functional role to ascertain superior genes for important traits and can offer breeder ready markers for developing ideotypes. This review highlights drought-induced damage to cotton plants at structural, physiological and molecular levels. It also discusses the opportunities for increasing drought tolerance in cotton either through modern gene editing technology like clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), zinc finger nuclease, molecular breeding as well as through crop management, such as use of appropriate fertilization, growth regulator application and soil amendments.

Structurally conserved C-RFa revealed prolactin releasing activity in vitro and gene expression changes in pituitary of seasonally acclimatized carp

Here we show the cloning and characterization of a novel homolog of prepro C-RFa cDNA from Cyprinus carpió. The deduced preprohormone precursor of 115 amino acids leads to a mature bioactive peptide of 20 amino acids with identical sequence to other teleost C-RFa. Modeling of the mature C-RFa peptide highlighted significant similarity to homologous human PrRP20, specifically the conserved amphipathic system defined by the C-terminal alpha-helix. Clearly, the synthetic C-RFa peptide stimulated prolactin release from primary cultured fish pituitary cells. For the first time, significant variation was shown in C-RFa mRNA and protein levels in the hypothalamus and pituitary between summer- and winter-acclimatized carp. Furthermore, C-RFa protein distribution in carp central nervous tissue was visualized by immunodetection in fibers and cells in hypothalamus, olfactory tract, cerebellum and pituitary stalk. In conclusion, we demonstrated the structure conservation of C-RFa in teleosts and mammals and immunopositive cells and fibers for C-RFa in brain areas. Finally, the increase of C-RFa expression suggests the participation of this hypothalamic factor in the mechanism of modulation in PRL expression in carp.

Cold resistance in plants: a mystery unresolved

Herbaceous temperate plants are capable of developing freezing tolerance when they are exposed to low nonfreezing temperatures. Acquired freezing tolerance involves extensive reprogramming of gene expression and metabolism. Recent full-genome transcript profiling studies, in combination with mutational and transgenic plant analyses, have provided a snapshot of the complex transcriptional network that operates under cold stress. The changes in expression of hundreds of genes in response to cold temperatures are followed by increases in the levels of hundreds of metabolites, some of which are known to have protective effects against the damaging effects of cold stress. Genetic analysis has revealed important roles for cellular metabolic signals, and for RNA splicing, export and secondary structure unwinding, in regulating cold-responsive gene expression and chilling and freezing tolerance. These results along with many of the others summarized here further our understanding of the basic mechanisms that plants have evolved to survive freezing temperatures. In addition, the findings have potential practical applications, as freezing temperatures are a major factor limiting the geographical locations suitable for growing crop and horticultural plants and periodically account for significant losses in plant productivity. Although, great progress has been made in the field but lacunae still remain since it appears that the cold resistance is more complex than perceived and involves more than one pathway.

Quantitative real-time PCR method to detect changes in specific transcript and total RNA amounts

Quantitative real-time PCR (qRT-PCR), used in conjunction with reverse transcriptase, has been applied to the determination of the number of copies of a transcript per unit mass of RNA, but did not indicate any change in the amount of total RNA per mass of tissue. In the present work, we described a simple method to use qRT-PCR to estimate the change in the amount of total RNA per unit mass of wheat (Triticum aestivum L.) tissue in response to cold temperature. Three qRT-PCR templates, i.e. control, cold-exposed, and one of RNA extracted from a sample consisting of equal masses of control and cold-exposed tissue, were analyzed. The number of copies of target transcript per unit mass of RNA was estimated from the three samples using standard qRT-PCR techniques. Equations describing the number of copies of the target sequence in each of the tissue samples were solved simultaneously to describe the relative proportion of the target sequence that originated from each tissue sample in the mixture, thereby providing an estimate of relative amounts of total RNA in the two tissues.

Las arterias pulmonares distales en los habitantes de las alturas / The pulmonary distal arteries at high altitude population

El estudio de las arterias pulmonares, en el hombre y en los animales que viven en las grandes alturas, ha demostrado la existencia de varios cambios morfológicos, como la muscularización de las arteriolas así como la proliferación de células musculares lisas en la íntima de las arterias distales. Estos cambios están relacionados con una vasoconstricción como respuesta a la hipoxia y al desarrollo de una hipertensión arterial pulmonar que, en algunos casos, se asocian con hipertrofia ventricular derecha e insuficiencia cardiaca congestiva, como en la enfermedad subaguda de la altura, descrita en el Himalaya y en los Andes en el hombre y en ciertas especies animales. Una posible pérdida de la respuesta vasoconstrictiva por transmisión genética a la hipoxia crónica se ha observado como una aclimatización o adaptación a las grandes alturas.