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Abiotic stressors, such as drought and high salinity, seriously affect plant growth, productivity, and quality. Maintaining reactive oxygen species (ROS) homeostasis and osmotic balance plays a crucial role in abiotic stress tolerance. β-amylase (BAM) hydrolyzes α-1,4-glycosidic bonds by releasing maltose from starch in the regulation of soluble sugars. However, the function and mechanism of BAMs related to abiotic stress resistance remain unclear in sweetpotato (Ipomoea batatas (L.) Lam.). In this study, we isolated a novel β-amylase gene IbBAM1.1 , which was strongly induced by PEG6000, NaCl, and maltose treatments in sweetpotato variety Yanshu25. Overexpression of IbBAM1.1 conferred enhanced tolerance to the drought and high salinity stressors in Arabidopsis thaliana. The activity of β-amylase and the degradation of starch were promoted under drought or salt stress. Accordingly, the contents of osmoprotectants, including maltose and proline were significantly higher in the transgenic lines than those in wild type (WT) plants. Less ROS, such as H 2 O 2 and O 2 −, accumulated in the overexpressing lines than in WT plants. Superoxide dismutase activity was strongly enhanced and the level of malondialdehyde was lower under the drought or salt treatment in transgenic plants. Taken together, these results demonstrate that IbBAM1.1 acted as a positive regulator, at least in part, by regulating the level of osmoprotectants to balance the osmotic pressure and activate the scavenging system to maintain ROS homeostasis in the plants. • IbBAM1.1 is induced by drought, high salinity and maltose treatments in sweetpotato. • Overexpression of IbBAM1.1 enhances drought and salt tolerance in transgenic plants. • IbBAM1.1 regulates ROS homeostasis and osmotic balance to enhance abiotic resistance. [ABSTRACT FROM AUTHOR]

Peanut is an important oilseed crop whose production is threatened by various abiotic and biotic stresses. Study of the molecular mechanism of salt tolerance could provide important information for the salt tolerance of this crop. WRKY transcription factors (TFs) are one of the largest TF families in plants and are involved in growth and development, defense regulation and the stress response. Here, we cloned a novel WRKY transcription factor gene belonging to the WRKY IIc subfamily, AhWRKY75 , from the salt-tolerant mutant M34. The expression of AhWRKY75 was induced by NaCl stress treatment. After salt treatment, AhWRKY75 -overexpressing peanuts grew better than wild-type plants. Furthermore, several genes related to the reactive oxygen species (ROS) scavenging system were up-regulated; the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly higher in transgenic lines than in non-transgenic control plants; and the malondialdehyde (MDA) and superoxide anion contents were significantly lower in transgenic lines than in control plants. The net photosynthetic rate (Pn), stomatal conductance (GS) and transpiration rate (Tr) of transgenic lines were significantly higher in transgenic plants than in control plants, and the intercellular CO 2 concentration (Ci) was significantly lower in transgenic plants than in control plants. These results demonstrated that the AhWRKY75 gene conferred salt tolerance in transgenic peanut lines by improving the efficiency of the ROS scavenging system and photosynthesis under stress treatment. This study identifies a novel WRKY gene for enhancing the tolerance of peanut and other plants to salt stress. • Grafted & self-grafted Hylocereus tolerate heat stress better vs non-grafted plants. • Grafted plants recover faster from heat stress and suffer less stem damage. • Grafting probably confers enhanced heat tolerance by inducing "cross-tolerance". [ABSTRACT FROM AUTHOR]

Peanut (Arachis hypogaea L.) is an allotetraploid oilseed crop worldwide due to its abundant high-quality oil production. Peanut oil stability and quality are determined by the relative proportions of saturated fatty acids (SFAs) and unsaturated fatty acids (UFAs). The principle approach to minimize the content of SFAs in peanut is to reduce the content of palmitic acid, which is linked to cardiovascular disease. Acyl-acyl carrier protein thioesterases (FATs) determine the types and levels of fatty acids that are exported them from the plastids. Two different classes of FAT have been classified into two families in plants, FatA and FatB. Among them, AhFatB has become the primary objective to genetically reduce the content of palmitic acid in peanut. Here, we identified 18 AhFatB genes in A. hypogaea genome and grouped into four major subfamilies through gene structures and phylogenetic relationships. Expression profiling of AhFatB genes was assessed using the publicly available RNA-seq data and qRT-PCR in 22 tissues. Using the CRISPR/Cas9 system, we designed two sgRNAs to edit the homologs AhFatB genes Arahy.4E7QKU and Arahy.L4EP3N , and identified different types of mutations. Additionally, we discovered mutations at Arahy.4E7QKU exhibited low palmitic acid and high oleic acid phenotypes. The obtained peanut mutants with altered SFAs content have great potential for improving peanut oil quality for human health. • A total of 18 AhFatB members were characterized in Arachis hypogaea L. • Mutations of AhFatB showed low palmitic and high oleic acid using CRISPR/Cas9 system. • AhFatB determined the oil profile and improved oil quality in peanut. [ABSTRACT FROM AUTHOR]