查看更多>>摘要：? 2022 The AuthorsShade is one of the recommended management solutions to mitigate the effects of heat stress, which is a major challenge for cocoa production globally. Nevertheless, there are limited studies to verify this hypothesis. Here, we evaluate the effects of heat and shade on cocoa physiology using experimental plots with six-month old potted seedlings in a randomized complete block design. Infrared heaters were applied for one month to increase leaf temperatures by an average of 5–7 oC (heat treatment) compared with no heat (unheated treatments), and shaded plants were placed under a shade net removing 60% of the light compared with no shade (sun treatments). Plants under heat treatments in sun and in shade showed severe reduction in photosynthesis. Measurements of chlorophyll fluorescence and photosynthetic light response curves indicated that heat caused damages at photosystem II and additionally resulted in lower rates of maximal photosynthesis. Temperature optima for photosynthesis were at 31–33 oC with only small differences between treatments, and as light saturation was reached at low PAR levels of 325 – 380 μmol m?2 s?1 in shade and 427 – 521 μmol m?2 s?1 in sun, ambient rates of photosynthesis were comparable between sun and shade treatments. Heat treatments resulted in decreased concentrations of chlorophyll and changed pigment composition, reduced specific leaf areas, and plant biomass. While shade may benefit cocoa seedlings, our results indicate that the positive effects may not be sufficient to counteract the negative effects of increased temperatures on cocoa physiology.
查看更多>>摘要：? 2022 Elsevier B.V.Noncoding RNAs are typically more than 200 nucleotides in lengths with indiscernible protein coding potential defined as long non-coding RNA (lncRNAs). LncRNAs play a versatile role in plant growth, development, and responses to various ecological perturbations particularly cold. However, a comprehensive identification of lncRNAs responsive to cold stress in B. napus has not been identified. The aim of the present study was to identify potential lncRNAs in cold tolerant (CT-C18) and cold-sensitive (CS-C6) B. napus varieties under cold stress. A total of 11073 lncRNAs were identified in both varieties of Brassica. In CT-C18 variety, 2394 and 3508 lncRNAs were expressed at 1d and 7d after cold stress, respectively. Furthermore, 3347 and 3872 lncRNAs were expressed at 1d and 7d in CS-C6 variety, respectively. Fifteen lncRNAs were found to be target mimics of 23 miRNAs. Additionally, a total of 16 lncRNAs were predicted as precursors of B. napus miRNAs seven miRNA family. Moreover, weighted gene co-expression network analysis revealed that four modules correlate with the expression status of protein-coding genes with lncRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis shown that out of those 170 gene were tagged with 60 Enzyme Code, and 101 GO terms. Our study increased the understanding of the expression and characterization of B. napus lncRNAs in response to cold stress, which may use as a reference for functional-based studies of targeting putative lncRNAs particularly under cold stress.
查看更多>>摘要：? 2022 Elsevier B.V.Sugar will eventually be exported transporter (SWEET) protein involved in various developmental and stress responses in plants. Here, we report the mechanisms and transcriptional regulatory pathway of the wheat TaSWEET14 in response to cadmium stress. Overexpression of TaSWEET14 improves cadmium stress tolerance and decreases cadmium accumulation in wheat grains. The overexpression of TaSWEET14 in wheat seedlings altered the expression pattern of the ion transporter genes NRAMP5, LCT1, HMA3, and IRT1. These genes were remarkably down-regulated in shoot tissues of TaSWEET14 transgenic wheat lines under cadmium stress. However, there was no significant difference in their expression levels in roots between the wild type (WT) and transgenic plants. In addition, the transgenic plants had a strong ability to remove reactive oxygen species and showed increased activity of antioxidant enzymes. Notably, the transgenic lines had significantly lower cellulose content but higher lignin content than the WT under cadmium stress. The cell wall cadmium content was also significantly higher in the transgenic lines. Lastly, we revealed that TaMYB41 binds directly to the promoter of TaSWEET14 to activate its transcription. This study describes a novel cadmium-responsive regulatory pathway in wheat and demonstrates that TaSWEET14 directly controls wheat cadmium accumulation by altering lignin content.
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Elsevier