A C2H2-type zinc finger transcription factor, MdZAT17, acts as a positive regulator in response to salt stress

Genome-wide analysis of C2H2 zinc finger family and their response to abiotic stresses in apple

C2H2-type zinc finger proteins are one of the most widely studied families in plants and play important roles in abiotic stress responses. In the present study, the physicochemical properties, chromosomal locations, evolutionary relationships, and gene structures of 54 C2H2 zinc finger protein (ZFP) family members were analyzed in apple. The MdC2H2-ZFP genes were phylogenetically clustered into seven subfamilies distributed in different densities on 16 chromosomes. The RNA-seq data from various tissues revealed that MdC2H2-ZFPs differentially expressed among root, stem, leaf, flower, and fruits. Quantitative analysis of its expression characteristics showed that the MdC2H2-ZFP genes were rapidly induced as exposure to abiotic stresses such as drought, salt and low temperature etc. Under drought stress, the expression of eight members was significantly up-regulated, and the highest was obtained from MdC2H2-17; as exposure to salt stress, nine MdC2H2-ZFPs was obviously up-regulated, with the highest expression of MdC2H2-13; and under low temperature stress, the expression of seven members was highly up-regulated, and MdC2H2-13 also demonstrated the highest expression which is same as the case under salt stress. Therefore, some members of MdC2H2-ZFP gene family considerably involve in the multiple abiotic stress responses, which may better understand the function of this family and facilitate the breeding of apple for stress tolerance.

Cloning and functional identification of apple LATERAL ORGAN BOUNDARY DOMAIN 3 (LBD3) transcription factor in the regulation of drought and salt stress

MAIN CONCLUSION

Overexpression of MdLBD3 in Arabidopsis reduced sensitivity to salt and drought stresses and was instrumental in promoting early flowering. Salt and drought stresses have serious effects on plant growth. LATERAL ORGAN BOUNDARY DOMAIN (LBD) proteins are a plant-specific transcription factors (TFs) family and play important roles in plants in resisting to abiotic stress. However, about the function of LBDs in apple and other woody plants is little known. In this study, protein sequences of the LBD family TFs in apples were identified which contained conserved LOB domains. The qRT-PCR analysis showed that the MdLBD3 gene was widely expressed in various tissues and organs. The subcellular localization assay showed that the MdLBD3 protein was localized in the nucleus. Ectopic expression of MdLBD3 in Arabidopsis positively regulated its salt and drought resistance, and promoted early flowering. Collectively, these results showed that MdLBD3 improved the abiotic stress resistance, plant growth and development. Overall, this study provided a new gene for breeding that can increase the abiotic stress tolerance in apple.

Genome-Wide Identification and Functional Analysis of NAP1 in Triticum aestivum

As a main molecular chaperone of histone H2A-H2B, nucleosome assembly protein 1 (NAP1) has been widely researched in many species. However, there is little research investigating the function of NAP1 in Triticum aestivum. To understand the capabilities of the family of NAP1 genes in wheat and the relationship between TaNAP1 genes and plant viruses, we performed comprehensive genome-wide analysis and quantitative real-time polymerase chain reaction (qRT-PCR) for testing expression profiling under hormonal and viral stresses. Our results showed that TaNAP1 was expressed at different levels in different tissues, with higher expression in tissues with high meristematic capacity, such as roots. Furthermore, the TaNAP1 family may participate in plant defense mechanisms. This study provides a systematic analysis of the NAP1 gene family in wheat and lays the foundation for further studies on the function of TaNAP1 in the response of wheat plants to viral infection.

The intertwining of Zn-finger motifs and abiotic stress tolerance in plants: Current status and future prospects

Environmental stresses such as drought, high salinity, and low temperature can adversely modulate the field crop's ability by altering the morphological, physiological, and biochemical processes of the plants. It is estimated that about 50% + of the productivity of several crops is limited due to various types of abiotic stresses either presence alone or in combination (s). However, there are two ways plants can survive against these abiotic stresses; a) through management practices and b) through adaptive mechanisms to tolerate plants. These adaptive mechanisms of tolerant plants are mostly linked to their signalling transduction pathway, triggering the action of plant transcription factors and controlling the expression of various stress-regulated genes. In recent times, several studies found that Zn-finger motifs have a significant function during abiotic stress response in plants. In the first report, a wide range of Zn-binding motifs has been recognized and termed Zn-fingers. Since the zinc finger motifs regulate the function of stress-responsive genes. The Zn-finger was first reported as a repeated Zn-binding motif, comprising conserved cysteine (Cys) and histidine (His) ligands, in Xenopus laevis oocytes as a transcription factor (TF) IIIA (or TFIIIA). In the proteins where Zn²⁺ is mainly attached to amino acid residues and thus espousing a tetrahedral coordination geometry. The physical nature of Zn-proteins, defining the attraction of Zn-proteins for Zn²⁺, is crucial for having an in-depth knowledge of how a Zn²⁺ facilitates their characteristic function and how proteins control its mobility (intra and intercellular) as well as cellular availability. The current review summarized the concept, importance and mechanisms of Zn-finger motifs during abiotic stress response in plants.

Functional Characterization of Sugar Beet M14 Antioxidant Enzymes in Plant Salt Stress Tolerance

Salt stress can cause cellular dehydration, which induces oxidative stress by increasing the production of reactive oxygen species (ROS) in plants. They may play signaling roles and cause structural damages to the cells. To overcome the negative impacts, the plant ROS scavenging system plays a vital role in maintaining the cellular redox homeostasis. The special sugar beet apomictic monosomic additional M14 line (BvM14) showed strong salt stress tolerance. Comparative proteomics revealed that six antioxidant enzymes (glycolate oxidase (GOX), peroxiredoxin (PrxR), thioredoxin (Trx), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase3 (DHAR3)) in BvM14 were responsive to salt stress. In this work, the full-length cDNAs of genes encoding these enzymes in the redox system were cloned from the BvM14. Ectopic expression of the six genes reduced the oxidative damage of transgenic plants by regulating the contents of hydrogen peroxide (H₂O₂), malondialdehyde (MDA), ascorbic acid (AsA), and glutathione (GSH), and thus enhanced the tolerance of transgenic plants to salt stress. This work has charecterized the roles that the antioxidant enzymes play in the BvM14 response to salt stress and provided useful genetic resources for engineering and marker-based breeding of crops that are sensitive to salt stress.

Effects of Salt Stress on the Morphology, Growth and Physiological Parameters of Juglansmicrocarpa L. Seedlings

In this study, to screen for walnut salt-tolerant rootstocks, Juglans microcarpa L. seedlings were treated in different NaCl concentrations (0, 50, 100, 200, and 300 mmol/L), and the growth situation of seedlings was observed. Moreover, we determined the physiological indexes of seedlings on different days (6, 12, 18, and 24 d) after treatment. The results showed that after salt stress, the external morphology of seedlings displayed salt injury, which manifested as yellowing, withering, curling, and falling off of leaves. High concentrations and long-term stress led to more serious damage, with numerous leaves undergoing withering and shedding. Salt stress significantly inhibited the growth of seedlings. With the increase in salt concentration and stress time, the chlorophyll content and photosynthetic parameters of seedlings reduced to varying degrees; the relative electrical conductivity (REC) and malondialdehyde (MDA) increased. Superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities generally increased, followed by a decrease; proline (Pro) accumulated; and soluble sugar (SS) content first increased and then decreased. In addition, it promoted the production of abscisic acid (ABA) and inhibited the synthesis of indole-3-acetic acid (IAA), gibberellic acid 3 (GA3), and zeatin riboside (ZR). It was found that J.microcarpa L. seedlings were more tolerant under 100 mmol/L salt stress, whereas the damage to growth was more severe at 200 mmol/L to 300 mmol/L salt stress.