Late embryogenesis-abundant (LEA) proteins are a large and highly diverse family believed to function in normal plant growth and development, and in protecting cells from abiotic stress. This study presents a characterisation of 74 Solanum tuberosum LEA (StLEA) proteins belonging to nine groups. StLEA genes have few introns (≤2) and are distributed on all chromosomes, occurring as gene clusters on chromosomes 1, 2, and 10. All four StASR (StLEA7 group) genes were concentrated on chromosome 4, suggesting their evolutionary conservation on one chromosome. Expression profiles of StLEA genes, in different tissues and in response to hormone and stress treatments, indicated that 71 StLEA genes had differential expression levels, of which 68 StLEA genes were differentially expressed in response to hormones and stress exposure in the potato. Continuous high expression of StASR-2, StLEA3-3, StDHN-3, StLEA2-29, and StLEA2-14 in different tissues indicated their contribution to plant development processes. StLEA2-14, StLEA2-31, StLEA3-3, StASR-1, and StDHN-1 were upregulated by six abiotic stresses, showing their tolerance to a wide spectrum of environmental stresses. Expression analysis of 17 selected StLEA genes in response to drought, salt, heavy metal, heat, and cold treatments by quantitative real-time polymerase chain reaction indicated that StLEA proteins may be involved in distinct signalling pathways. Taken together, StLEA3, StDHN, and StASR subgroup genes may be excellent resources for potato defence against environmental stresses. These results provide valuable information and robust candidate genes for future functional analysis aimed at improving the stress tolerance of the potato.

Potato is an important food crop and its production is susceptible to drought. Drought stress in crop growth is usually multiple- or long-term. In this study, the drought tolerant potato landrace Jancko Sisu Yari was treated with drought stress, rehydration and re-dehydration, and RNA-seq was applied to analyze the characteristics of gene regulation during these treatments. The results showed that drought-responsive genes mainly involved photosynthesis, signal transduction, lipid metabolism, sugar metabolism, wax synthesis, cell wall regulation, osmotic adjustment. Potato also can be recovered well in the re-emergence of water through gene regulation. The recovery of rehydration mainly related to patatin, lipid metabolism, sugar metabolism, flavonoids metabolism and detoxification besides the reverse expression of the most of drought-responsive genes. The previous drought stress can produce a positive responsive ability to the subsequent drought by drought hardening. Drought hardening was not only reflected in the drought-responsive genes related to the modified structure and cell components, but also in the hardening of gene expression or the “memory” of drought-responsive genes. Abundant genes involved photosynthesis, signal transduction, sugar metabolism, protease and protease inhibitors, flavonoids metabolism, transporters and transcription factors were subject to drought hardening or memorized drought in potato.

Expansin is a type of cell wall elongation and stress relaxation protein involved in various developmental processes and stress resistances in plant. In this study, we identified 36 potato ( Solanum tuberosum L.) genes belonging to the expansin ( StEXP ) gene family from the genome reference. These genes included 24 α-expansins ( StEXPAs ), five β-expansins ( StEXPBs ), one expansin-like A ( StEXLA ) and six expansin-like B ( StEXLBs ). The RNA-Seq analysis conducted from a variety of tissue types showed 34 expansins differentially expressed among tissues, some of which only expressed in specific tissues. Most of the StEXPAs and StEXPB2 transcripts were more abundant in young tuber compared with other tissues, suggesting they likely play a role in tuber development. There were 31 genes, especially StEXLB6 , showed differential expression under the treatments of ABA, IAA and GA3, as well as under the drought and heat stresses, indicating they were likely involved in potato stress resistance. In addition, the gene co-expression analysis indicated the StEXLBs likely contribute to a wider range of stress resistances compared with other genes. We found the StEXLA and six StEXLBs expressed differently under a range of abiotic stresses (salt, alkaline, heavy metals, drought, heat, and cold stresses), which likely participated in the associated signaling pathways. Comparing with the control group, potato growing under the drought or heat stresses exhibited up-regulation of the all six StEXLB genes in leaves, whereas, the StEXLB3 , StEXLB4 , StEXLB5 and StEXLB6 showed relatively higher expression levels in roots. This suggested these genes likely played a role in the drought and heat tolerance. Overall, this study has shown the potential role of the StEXP genes in potato growth and stress tolerance, and provided fundamental resources for the future studies in potato breeding.

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IntroductionDiabetic cardiomyopathy (DC) is associated with impaired diastolic function. Hyperglycemia-mediated oxidative stress and apoptosis are the major factors responsible for DC. Also NADPH oxidase is the main source of ROS in cardiac cells or cardiomyocytes. Here we evaluated the effect of fucoxanthin (FXN) on high glucose cultured neonatal rat cardiomyocytes.Material and methodsFor the study, Iry neonatal rat cardiomyocytes were cultured in a high glucose environment (30 mM/l) in the presence and absence of FXN. Apoptosis, cell viability, activity of NADPH oxidase and expression level of its subunits, levels of MDA and activity of endogenous antioxidant enzymes were studied. We also confirmed the involved pathway by studying the expression of AMPK, GSK-3 and Akt in the cardiomyocytes.ResultsThe high glucose environment increased the production of ROS, and FXN decreased the oxidative burden by inhibiting ROS in cultured neonatal rat cardiomyocytes. FXN inhibited the activity of NADPH oxidase and Rac1 also increased the expression of its subunits. Treatment of FXN reversed the MDA, CAT, GSHpx, SOD activity and GSH contents. FXN down-regulated the levels of Bax and up-regulated the levels of Bcl-2 (anti-apoptotic protein); treatment protected the cardiomyocytes from injury. Also, FXN increased the levels of pAMPK in cardiac cells treated with high glucose. The pharmacological inhibitor of AMPK abolished the activities of FXN in high glucose induced cardiomyocytes.ConclusionsFXN exerted protective action on cardiac cells subjected to high glucose-mediated apoptosis by suppressing NADPH oxidase-mediated production of ROS and maintaining the antioxidant defense in the tissues. The attenuating activity of FXN was propagated via the AMPK cascade.