The rice cultivar ( L.) BRS AG, developed by Embrapa Clima Temperado, is the first cultivar designed for purposes other than human consumption. It may be used in ethanol production and animal feed. Different abiotic stresses negatively affect plant growth. Soil salinity is responsible for a serious reduction in productivity. Therefore, the objective of this study was to evaluate the gene expression and the activity of antioxidant enzymes (SOD, CAT, APX and GR) and identify their functions in controlling ROS levels in rice plants, cultivar BRS AG, after a saline stress period. The plants were grown in vitro with two NaCl concentrations (0 and 136 mM), collected at 10, 15 and 20 days of cultivation. The results indicated that the activity of the enzymes evaluated promotes protection against oxidative stress. Although, there was an increase of reactive oxygen species, there was no increase in MDA levels. Regarding genes encoding isoforms of antioxidant enzymes, it was observed that -, -, -, -, -, -, , and were the most responsive. The increase in the transcription of all genes among evaluated isoforms, except for, which remained stable, contributed to the increase or the maintenance of enzyme activity. Thus, it is possible to infer that the cv. BRS AG has defense mechanisms against salt stress.

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Calcium-dependent protein kinases (CDPKs) are encoded by a large gene family and play important roles against biotic and abiotic stresses and in plant growth and development. To date, little is known about the CDPK genes in strawberry (Fragaria x ananassa). In this study, analysis of Fragaria x ananassa CDPK gene family was performed, including gene structures, phylogeny, interactome and expression profiles. Nine new CDPK genes in Fragaria x ananassa were identified based on RNA-seq data. These identified strawberry FaCDPK genes were classified into four main groups, based on the phylogenetic analysis and structural features. FaCDPK genes were differentially expressed during fruit development and ripening, as well as in response to abiotic stress (salt and drought), and hormone (abscisic acid) treatment. In addition, the interaction network analysis pointed out proteins involved in the ABA-dependent response to plant stress via Ca 2+ signaling, especially RBOHs. To our knowledge, this is the first report on CDPK families in Fragaria x ananassa, and it will provide valuable information for development of biofortified fruits and stress tolerant plants. Plants are constantly exposed to stress conditions, such as drought, low or high temperature, and high salinity 1. Plants adapt to these conditions by capturing external signals and modulating their responses using complex mechanisms. These mechanisms involve the perception of the stimulus and subsequent signal transduction, which lead to the activation of various chemical, molecular, biochemical, and physiologic changes, improving plant plasticity 2. The calcium ion (Ca 2+) plays central roles in the regulation of different physiological processes in plants as an important secondary messenger. Transient changes in the cytoplasmic concentration of Ca 2+ are detected by several types of sensor proteins that initiate rapid signal transduction processes by triggering cascades of phosphorylation events. Several major classes of Ca 2+ binding proteins have been characterized in plants, including Ca 2+-dependent protein kinases (CDPK), calmodulin (CaM), CAM-like proteins (CML), and calcineurin B-like proteins (CBL) 3-6. Among these, CDPK constitutes a large calcium-sensing family only found in plants, protists, oomycetes, and green algae, and not in animals and fungi 7. CDPK structures include four domains: N-terminal, self-regulatory/autoinhibitory, serine/threonine kinase, and finally calmodulin-like regulatory domains (CaM-LD) 8. The CaM-LD domain contains three or four EFhand Ca 2+-binding motifs that recognize distinct Ca 2+ signatures with variable affinities. The C-terminal lobe of the CaM-LD binds Ca 2+ with high affinity. At low Ca 2+ levels, the structure is stabilized by the interaction of this lobe with the auto-inhibitory region of the protein. Otherwise, a conformational change induced by the binding of Ca 2+ to the low-affinity N-terminal lobe of CaM-LD results in the release of the auto-inhibition 9,10. CDPKs are involved in stress signaling, hormone respon...

This study evaluated the metabolism of proline in rice based on the expression pattern of genes involved in biosynthesis and catabolism of amino acid and determined the correlation with the proline content produced under stress. In stage V4, genotypes with a differentiated response to salinity and low-temperature stresses were exposed separately to two test conditions: 150 mM NaCl and 13°C. Proline increased in both genotypes and stresses. The expression of P5CS1 was increased in both genotypes and conditions, while P5CS2 was responsive in the sensitive genotype under salinity. High correlations between proline content/P5CS1, proline content/P5CS2, P5CS1/P5CR, and P5CS2/P5CR were observed for the tolerant genotype under salt stress. The correlation between proline content/PDH was 0.42 and-0.13 (tolerant genotype) and-0.54 and 0.15 (sensitive genotype) under salinity and cold, respectively. P5CDH was positively correlated with proline content under salinity for both genotypes. Under salt stress, there was a positive correlation between proline content/OAT in the tolerant genotype. It was concluded that the increase in proline content is greater for the tolerant genotype. Under salt stress, the levels of transcript genes are more correlated with the proline content in the tolerant genotype, while at 13°C, the correlation of the sensitive genotype was higher.