Functional conservation of RNAs between different species is a key argument for their importance. While few long non-coding RNAs are conserved at the sequence level, many long non-coding RNAs have been identified that only share a position relative to other genes. It remains largely unknown whether and how these lncRNAs are conserved beyond their position. In Arabidopsis thaliana, the lncRNA COOLAIR is transcribed antisense from FLOWERING LOCUS C (FLC) in response to cold. Despite relatively low sequence similarity, the COOLAIR expression pattern and in vitro RNA secondary structure are highly conserved across the family Brassicaceae, which originated some 50 mya. It is unclear, however, whether COOLAIR functions in distantly related species such as monocots, which diverged some 150 mya. Here, we identified antisense lncRNAs from FLC homologs in various monocot species that share no sequence similarity with A. thaliana COOLAIR. Yet similar to COOLAIR, we found that BdODDSOC1 antisense (BdCOOLAIR1) and BdODDSOC2 antisense (BdCOOLAIR2) are induced by cold in a Brachypodium distachyon winter accession. Across B. distachyon accessions, the sequences of BdCOOLAIR1 and BdCOOLAIR2 are less conserved than exons but more conserved than flanking regions, suggesting a function for the transcript itself. Knock down of the BdODDSOC2 non-overlapping BdCOOLAIR2 transcript did not show a morphological phenotype, but did result in significantly higher BdODDSOC2 expression during cold, indicating that BdCOOLAIR2 performs a role in cis in the rate of BdODDSOC2 silencing. This functional similarity between eudicot and monocot species reveals ancient conservation or convergent evolution of FLC antisense transcription. Either scenario supports its functional importance.

The present study was conducted to evaluate the physiological and biochemical changes in some thermotolerant and thermosensitive chilli (Capsicum annuum L.) genotypes. Fourteen chilli genotypes (SL 461, PP 404, DL 161, MS 341, VR 521, PB 405, PS 403, SD 463, FL 201, AC 102, S 343, SL 462 and SL 464 along with sensitive check [Royal Wonder of bell pepper] were evaluated for heat tolerance. The observations on morpho-physiological and biochemical parameters were recorded at 45, 65, 85 and 105 days after transplanting (DAT) (high temperature period). On the basis of our studies, genotypes S 343, AC 102 and FL 201 were found to be relatively thermotolerant. However, high temperature markedly decreased the photosynthetic activity of chilli plants by decreasing the photosynthetic pigments in leaf chloroplasts of all the genotypes. The levels of ascorbic acid, total soluble sugars and total phenols increased in the leaves of all the genotypes with the maturity of the crop. Electrolyte leakage and proline content also increased with rise in temperature. Genotypes AC 102 and S 343 were able to accumulate the maximum ascorbic acid, proline, total soluble sugars and total phenols under heat stress conditions. Decrease in fruit set percent led to reduction in the total yield per plant. Maximum yield was observed in genotype S 343 followed by FL 201.

A phytohormone may be defined as an organic substance other than a nutrient active in very minute amounts which is formed in certain parts of all plants and which is usually translocated to other sites, where it evokes specific biochemical, physiological and morphological responses. The gaseous plant hormone ethylene modulates many internal processes and growth responses to environmental stimuli. Ethylene is known to exert its effects by altering gene expression both at transcriptional and post-transcriptional level. Ethylene has long beenrecognized as a growth inhibitor, but evidence is accumulating that ethylene can also promote growth. Therefore, the concept of ethylene as a general growth inhibitor needs reconsideration. Different authors screened various concentrations viz. 100 ppm, 150 ppm which promotes the plant growth in groundnut, soybean, mustard, barley, pigeonpea etc. The lower concentration of ethylene (100ppm) has increased the yield by 17 percent in pigeonpea. It increased the yield by manipulating source-sink relationships and flower retention The present study highlights the various processes of growth stimulated by ethylene and its use in enhancing yield of various crop species. It could be inferred that lower concentration of ethrel sprayed at pre-flowering stage promoted the growth and yield of various crops (barley, corn, groundnut, pigeonpea, soybean etc.).

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