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• UBC13 is required for Lys63-linked polyubiquitination and innate immune responses in mammals, but its functions in plant immunity remain to be defined. • Here we used genetic and pathological methods to evaluate roles of Arabidopsis UBC13 in response to pathogens and environmental stresses. • Loss of UBC13 failed to activate the expression of numerous cold-responsive genes and resulted in hypersensitivity to low-temperature stress, indicating that UBC13 is involved in plant response to low-temperature stress. Furthermore, the ubc13 mutant displayed low-temperature-induced and salicylic acid-dependent lesion mimic phenotypes. Unlike typical lesion mimic mutants, ubc13 did not enhance disease resistance against virulent bacterial and fungal pathogens, but diminished hypersensitive response and compromised effector-triggered immunity against avirulent bacterial pathogens. UBC13 differently regulates two types of programmed cell death in response to low temperature and pathogen. The lesion mimic phenotype in the ubc13 mutant is partially dependent on SNC1. UBC13 interacts with an F-box protein CPR1 that regulates the homeostasis of SNC1. However, the SNC1 protein level was not altered in the ubc13 mutant, implying that UBC13 is not involved in CPR1-regulated SNC1 protein degradation. • Taken together, our results revealed that UBC13 is a key regulator in plant response to low temperature and pathogens.

Summary High‐temperature (HT) stress at flowering stage causes significant damage to soybean, including pollen abortion and fertilization failure, but few genes involved in male fertility regulation under HT stress in soybean have been characterized. Here, we demonstrated that miR156b–GmSPL2b module involved in male fertility regulation of soybean cytoplasmic male sterility (CMS)‐based restorer line under HT stress. Overexpression of miR156b decreased male fertility in soybean CMS‐based restorer line and its hybrid F1 with CMS line under HT stress. RNA‐seq analysis found that miR156b mediated male fertility regulation in soybean under HT stress by regulating the expression of pollen development and HT response related genes. Metabolomic analysis of miR156bOE revealed reduction in flavonoid content under HT stress. Integrated transcriptomic and metabolomic analysis showed that the overexpression of miR156b caused flavonoid metabolism disorder in soybean flower bud under HT stress. Knockout of GmSPL2b also decreased the thermotolerance of soybean CMS‐based restorer line during flowering. Moreover, GmSPL2b turned out to be directly bounded to the promoter of GmHSFA6b. Further verification indicated that GmHSFA6b overexpression enhanced HT tolerance in Arabidopsis during flowering. Substance content and gene expression analysis revealed that miR156b–GmSPL2b may mediate reactive oxygen species clearance by regulating flavonoid metabolism, thus participating in the regulation of male fertility in soybean under HT stress. This study not only provided important progress for understanding the molecular mechanism of miR156b–GmSPL2b regulating the male fertility of soybean CMS‐based restorer line under HT stress, but also provided genetic resources and theoretical basis for creating HT‐tolerant strong restorer lines.

Aim: Species distributions along an environmental gradient are often not symmetric but skewed towards one end of the gradient. Various explanations for this skewness have been proposed but the patterns of niche asymmetry along extensive environmental gradients have been rarely explored. In this study, we tested three predictions of asymmetric abiotic stress limitation (AASL) hypothesis that predicts a steeper decrease in the probability of occurrence towards the more stressful end of a plant distributional range. Location: Ladakh, arid Himalayas, where drought stress dominates in the lower elevation, whilst the cold stress dominates in the upper elevations. Methods: Using data from 4062 plots (2640-6150 m a.s.l.), we explored the shapes of response curves of 395 vascular plant species through Huisman-Olff-Fresco models. We compared the observed patterns of niche asymmetry along the elevational gradient with null models. Results: Species with symmetric response curves (61.5%) prevailed at lower elevations, whilst species with left-skewed responses (36.2%) were significantly underrepresented up to 3750 m a.s.l. and occurred significantly more frequently at 5150-5450 m a.s.l. Right-skewed responses were rare (2.3%) along the whole gradient. The steepness of the response increased with elevation. Response types were found in similar proportions across different habitats and functional groups. Main conclusions: Our results support the predictions of AASL hypothesis for cold limits, but not for dry limits. The low proportion of right-skewed responses over the entire gradient suggests an effective adaptation of the local flora to arid conditions, or sufficient opportunity to avoid drought stress through the presence of favourable habitat patches. The accumulation of skewed responses at high elevations likely reflects shared physiological limits of many steppe species, whose distribution abruptly ends at the transition between steppe and alpine zones. Cold, therefore, represents a stronger barrier to species distribution than drought.

Previous studies have indicated that Cranoglanis bouderius and Pangasianodon hypophthalmus clustered into a sister group. However, there was a significant difference in their minimum tolerated temperatures. To reveal the temperature adaptation‐related genes, a genome‐wide comparative analysis was performed. First, a chromosome‐level draft genome of C. bouderius was constructed in this study. The genome assembly was 999.18 Mb in size with a contig N50 of 20.47 Mb. Then, an additional 118.98 Gb of Hi‐C data was applied to assemble contigs into scaffolds and 910.59 Mb was anchored and orientated onto 38 chromosomes of C. bouderius . A total of 24,165 protein‐coding genes were predicted from the genome with 22,920 (94.84%) genes functionally annotated. Genome‐wide comparative analysis revealed that the genes related to resistance to low‐temperature stress were mainly enriched into the gene ontology (GO) terms associated with mitochondrial fusion and calcium ion transport. Further, the low‐temperature stress test on the C. bouderius and P. hypophthalmus also revealed that the C. bouderius can better control the homeostasis of calcium ions in cells than P. hypophthalmus , and then better maintain the dynamic changes of mitochondrial fusion and fission in cells, thereby resisting cell damage caused by low‐temperature stress.

The genotype WS-1, previously identified from novel wucai germplasm, is tolerant to both low-temperature (LT) and high-temperature (HT) stress. However, it is unclear which signal transduction pathway or acclimation mechanisms are involved in the temperature-stress response. In this study, we used the proteomic method of tandem mass tag (TMT) coupled with liquid chromatography-mass spectrometry (LC-MS/MS) to identify 1022 differentially expressed proteins (DEPs) common to WS-1, treated with either LT or HT. Among these 1022 DEPs, 172 were upregulated in response to both LT and HT, 324 were downregulated in response to both LT and HT, and 526 were upregulated in response to one temperature stress and downregulated in response to the other. To illustrate the common regulatory pathway in WS-1, 172 upregulated DEPs were further analyzed. The redox homeostasis, photosynthesis, carbohydrate metabolism, heat-shockprotein, and chaperones and signal transduction pathways were identified to be associated with temperature stress tolerance in wucai. In addition, 35S:BcccrGLU1 overexpressed in Arabidopsis, exhibited higher reduced glutathione (GSH) content and reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and less oxidative damage under temperature stress. This result is consistent with the dynamic regulation of the relevant proteins involved in redox homeostasis. These data demonstrate that maintaining redox homeostasis is an important common regulatory pathway for tolerance to temperature stress in novel wucai germplasm.

With global warming and an increase in the frequency of extreme heat events, uncertainty has arisen about the survival and fertility of insects that are enemies in the wild. In this study, we employed the generalized linear model (GLMs) for analysis to elucidate the effects of short‐term high temperatures on the survival, fecundity, and progeny of Microplitis manilae Ashmead (Hymenoptera: Braconidae), a key parasitic natural enemy of early instar larvae of Spodoptera litura Fabricius (Lepidoptera: Noctuidae). We conducted laboratory tests to assess the survival and lifespan of M. manilae adults at high temperatures of 35°C, 37°C, and 39°C, with exposure durations of 1, 3, 5, 7, and 9 h. We also evaluated the fecundity and longevity of the F1 generation adults, as well as the development of the F2 generation, following exposure at the same high temperatures for 5 h. The results indicated that M. manilae adult stages were significantly affected by elevated temperatures across different exposure durations, particularly when the duration exceeded 5 h. Under different high‐temperature exposures for 5 h, fecundity and longevity were significantly suppressed in the F1 generation, along with impaired growth and development in the F2 generation when the temperature exceeded 39°C. This study reveals the effects of short‐term high‐temperature stress on the survival, reproduction, and progeny development of M. manilae. It provides a theoretical basis for understanding the biological evolution mechanism of M. manilae in response to thermal stress and the biological control of pests by M. manilae in high‐temperature seasons. This study reveals the effects of short‐term high‐temperature stress on the survival, reproduction, and progeny development of M. manilae. It provides a theoretical basis for understanding the biological evolution mechanism of M. manilae in response to thermal stress and the biological control of pests by M. manilae in high‐temperature seasons.

Extreme temperature events as a consequence of global climate change result in a significant decline in rice yield. A two year phytotron experiment was conducted using three temperature levels and two heating durations to compare the effects of heat stress at booting (BT), flowering (FL), and combined (BT + FL) stages on rice yield and yield components. Compared with T1 (Tmean of 27 °C), heat stress at BT + FL and BT stages produced more regenerated tillers and compensated more for yield loss than heat stress at FL. Heat stress at BT + FL stages alleviated spikelet sterility and yield loss of original tillers compared to heat stress at FL. The greater variation of yield per plant (YPP) under heat stress at flowering as compared to BT and BT + FL stages was accompanied by a higher decrease in spikelet fertility, while, at BT and BT + FL stages, spikelet number per plant and 1000-grain weight also contributed well to variation in yield. Furthermore, heat stress during BT and BT + FL stages caused a significant decline in spikelet fertility of the upper part of panicles, followed by middle and lower parts, while heat stress at the FL stage responded inversely. For every 1 °C day increase in heat degree days at BT, FL, and BT + FL stages, YPPO (only original tillers) declined by 2.9%, 2.5%, and 6.0%, and YPPT (including original + regenerated tillers) decreased by 5.8%, 2.7%, and 2.2%, respectively. The projected alleviation effects under BT + FL stages of heat stress in contrast to single-stage heat stress would help to accurately estimate rice yield under extreme temperature events, as well as to develop a heat-tolerant rice cultivar.

In the context of global warming, the frequency of severe weather occurrences, such as unexpected cold spells and heat waves, will grow, as well as the intensity of these natural disasters. Lizards, as a large group of reptiles, are ectothermic. Their body temperatures are predominantly regulated by their environment and temperature variations directly impact their behavior and physiological activities. Frequent cold periods and heat waves can affect their biochemistry and physiology, and often their ability to maintain their body temperature. Mitochondria, as the center of energy metabolism, are crucial for maintaining body temperature, regulating metabolic rate, and preventing cellular oxidative damage. Here, we used RT-qPCR technology to investigate the expression patterns and their differences for the 13 mitochondrial PCGs in Sphenomorphus incognitus (Squamata:Scincidae), also known as the brown forest skink, under extreme temperature stress at 4 °C, 8 °C, 34 °C, and 38 °C for 24 h, compared to the control group at 25 °C. In southern China, for lizards, 4 °C is close to lethal, and 8 °C induces hibernation, while 34/38 °C is considered hot and environmentally realistic. Results showed that at a low temperature of 4 °C for 24 h, transcript levels of ATP8, ND1, ND4, COI, and ND4L significantly decreased, to values of 0.52 ± 0.08, 0.65 ± 0.04, 0.68 ± 0.10, 0.28 ± 0.02, and 0.35 ± 0.02, respectively, compared with controls. By contrast, transcript levels of COIII exhibited a significant increase, with a mean value of 1.86 ± 0.21. However, exposure to 8 °C for 24 h did not lead to an increase in transcript levels. Indeed, transcript levels of ATP6, ATP8, ND1, ND3, and ND4 were significantly downregulated, to 0.48 ± 0.11, 0.68 ± 0.07, 0.41 ± 0.08, 0.54 ± 0.10, and 0.52 ± 0.07, respectively, as compared with controls. Exposure to a hot environment of 34 °C for 24 h led to an increase in transcript levels of COI, COII, COIII, ND3, ND5, CYTB, and ATP6, with values that were 3.3 ± 0.24, 2.0 ± 0.2, 2.70 ± 1.06, 1.57 ± 0,08, 1.47 ± 0.13, 1.39 ± 0.56, and 1.86 ± 0.12, respectively, over controls. By contrast, ND4L exhibited a significant decrease (to 0.31 ± 0.01) compared with controls. When exposed to 38 °C, the transcript levels of the 13 PCGs significantly increased, ranging from a 2.04 ± 0.23 increase in ND1 to a 6.30 ± 0.96 rise in ND6. Under two different levels of cold and heat stress, the expression patterns of mitochondrial genes in S. incognitus vary, possibly associated with different strategies employed by this species in response to low and high temperatures, allowing for rapid compensatory adjustments in mitochondrial electron transport chain proteins in response to temperature changes. Furthermore, this underscores once again the significant role of mitochondrial function in determining thermal plasticity in reptiles.

Tomato fruits ripened 95, 65, 46 and 42d after flower opening when plants were grown under controlled environmental conditions at 14, 18, 22 and 26°C, respectively. A similar response to temperature was observed when the temperature of individual trusses was modified while the plants were grown at 20°C. These data were used to develop a thermal time model for fruit maturation. However, when buds/fruits were heated at different stages in their development, the thermal time model proved to be a poor predictor of the time of ripening. Fruits were more sensitive to elevated temperature in their later stages of maturation. Temperature also affected the rates of fruit growth in volume; these could be adequately described using a Gompertz function. Low temperatures reduced absolute volume growth rates and delayed the time at which the absolute growth rate became maximal. However, the response of fruit growth to temperature differed when only the temperature of the fruits was modified. There was a tendency towards small parthenocarpic fruits at both high (26°C) and low (14°C) temperature regimes which, combined with low flower numbers and poor fruit set at 26°C, resulted in low fruit yields. Temperature also affected the shoot dry matter content and partitioning.

Climate change is a universal challenge that threatens the very existence of life on planet Earth. One of the most sensitive areas to climate change is agriculture. Climate change affects precipitation, cyclones, clouds, temperature, humidity, and CO2 levels. All these factors affect plant productivity which poses another grave concern in feeding the ever-increasing population. The productivity in terms of crop yield is reduced due to a direct correlation between phenology and climate change. The reproductive organs of a plant and other parameters that define good fertility of a species are all affected by the increasing temperatures during their vegetative and reproductive phases of growth and development. Thus, this review is an attempt to understand the effect of climate change on the reproductive structures of plants and discuss the short-term and long-term adaptations in plants and agriculture as mitigation measures to combat the significant yield loss in developing countries.