FvZFP1 confers transgenic Nicotiana benthamiana resistance against plant pathogens and improves tolerance to abiotic stresses

Overexpression of StERECTA enhances drought tolerance in Arabidopsis thaliana

Drought is a major abiotic stresses that severely hinder plant growth and agricultural productivity. The receptor-like kinase gene, ERECTA, has been proved to play important role in promoting the response to abiotic stress in crops. However, the specific molecular mechanisms underlying the drought resistance mediated by ERECTA in potato (Solanum tuberosum L.) are not well understood. In this study, sequence analysis confirmed that the StERECTA gene contains eight leucine-rich repeat (LRR) domains and an S_TKc domain, and these domains were highly conserved in Solanaceae family. Under drought stress, Arabidopsis thaliana strains overexpressing StERECTA showed increased biomass, proline (PRO) content, and antioxidant enzyme activities compared to the wild-type strains while the mutant ERECTA strain (er105) exhibited opposite phenotype. Additionally, StERECTA overexpression upregulated the expression of drought response marker genes (LEA3, DREB2A and P5CS1), improved levels of ABA and auxin, reduced stomatal density and relative expression level of stomatal development related genes (SPCH, FAMA and MUTE). Furthermore, Co-immunoprecipitation (Co-IP) assays demonstrated that StERECTA physically interacted with the YODA protein. In conclusion, our study provides new insights into the role and regulatory mechanism of StERECTA in response to drought stress. These findings may serve as a basis for genetic improvement of potato to enhance their tolerance to abiotic stress.

Overexpression of the NbZFP1 encoding a C3HC4-type zinc finger protein enhances antiviral activity of Nicotiana benthamiana

Viral diseases are crucial determinants affecting tobacco cultivation, leading to a substantial annual decrease in production. Previous studies have demonstrated the regulatory function of the C3HC4 family of plant zinc finger proteins in combating bacterial diseases. However, it remains to be clarified whether this protein family also plays a role in regulating resistance against plant viruses. In this study, the successful cloning of the zinc finger protein coding gene NbZFP1 from Nicotiana benthamiana has been achieved. The full-length coding sequence of NbZFP1 is 576 bp. Further examination and analysis of this gene revealed its functional properties. The induction of NbZFP1 transcription in N. benthamiana has been observed in response to TMV, CMV, and PVY. Transgenic N. benthamiana plants over-expressing NbZFP1 demonstrated a notable augmentation in the production of chlorophyll a (P < 0.05). Moreover, NbZFP1-overexpressing tobacco exhibited significant resistance to TMV, CMV, and PVY, as evidenced by a decrease in virus copies (P < 0.05). In addition, the defense enzymes activities of PAL, POD, and CAT experienced a significant increase (P < 0.05). The up-regulated expression of genes of NbPAL, NbNPR1 and NbPR-1a, which play a crucial role in SA mediated defense, indicated that the NbZFP1 holds promise in enhancing the virus resistance of tobacco plant. Importantly, the results demonstrate that NbZFP1 can be considered as a viable candidate gene for the cultivation of crops with enhanced virus resistance.

A hierarchical model of ABA-mediated signal transduction in tea plant revealed by systematic genome mining analysis and interaction validation

As a critical signaling molecule, ABA plays an important role in plant growth, development and stresses response. However, tea plant [Camellia sinensis (L.)], an important economical perennial woody plant, has not been systematically reported in response to ABA signal transduction in vivo. In this study, we mined and identified the gene structure of CsPYL/CsPP2C-A/CsSnRK gene families in the ABA signal transduction pathway through the genome-wide analysis of tea plants. Spatiotemporal expression and stress response (drought, salt, chilling) expression patterns were characterized. The results showed that most members of CsPYLs were conserved, and the gene structures of members of A-type CsPP2Cs were highly similar, whereas the gene structure of CsSnRK2s was highly variable. The transcription levels of different family members were differentially expressed with plant growth and development, and their response to stress signal patterns was highly correlated. The expression patterns of CsPYL/CsPP2C-A/CsSnRK2 gene family members in different tissues of tea plant cuttings after exogenous ABA treatment were detected by qRT-PCR, and the hierarchical model of ABA signaling was constructed by correlation analysis to preliminarily obtain three potential ABA-dependent signaling transduction pathways. Subsequently, the protein interaction of the CsPYL4/7-CsPP2C-A2-CsSnRK2.8 signaling pathway was verified by yeast two-hybrid and surface plasmon resonance experiments, indicating that there is specific selectivity in the ABA signaling pathway. Our results provided novel insights into the ABA-dependent signal transduction model in tea plant and information for future functional characterizations of stress tolerance genes in tea plant.

Silencing of the calcium-dependent protein kinase TaCDPK27 improves wheat resistance to powdery mildew

BACKGROUND

Calcium ions (Ca²⁺), secondary messengers, are crucial for the signal transduction process of the interaction between plants and pathogens. Ca²⁺ signaling also regulates autophagy. As plant calcium signal-decoding proteins, calcium-dependent protein kinases (CDPKs) have been found to be involved in biotic and abiotic stress responses. However, information on their functions in response to powdery mildew attack in wheat crops is limited.

RESULT

In the present study, the expression levels of TaCDPK27, four essential autophagy-related genes (ATGs) (TaATG5, TaATG7, TaATG8, and TaATG10), and two major metacaspase genes, namely, TaMCA1 and TaMCA9, were increased by powdery mildew (Blumeria graminis f. sp. tritici, Bgt) infection in wheat seedling leaves. Silencing TaCDPK27 improves wheat seedling resistance to powdery mildew, with fewer Bgt hyphae occurring on TaCDPK27-silenced wheat seedling leaves than on normal seedlings. In wheat seedling leaves under powdery mildew infection, silencing TaCDPK27 induced excess contents of reactive oxygen species (ROS); decreased the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT); and led to an increase in programmed cell death (PCD). Silencing TaCDPK27 also inhibited autophagy in wheat seedling leaves, and silencing TaATG7 also enhanced wheat seedling resistance to powdery mildew infection. TaCDPK27-mCherry and GFP-TaATG8h colocalized in wheat protoplasts. Overexpressed TaCDPK27-mCherry fusions required enhanced autophagy activity in wheat protoplast under carbon starvation.

CONCLUSION

These results suggested that TaCDPK27 negatively regulates wheat resistance to PW infection, and functionally links with autophagy in wheat.

Isolation and Functional Analysis of MbCBF2, a Malus baccata (L.) Borkh CBF Transcription Factor Gene, with Functions in Tolerance to Cold and Salt Stress in Transgenic Arabidopsis thaliana

CBF transcription factors (TFs) are key regulators of plant stress tolerance and play an integral role in plant tolerance to adverse growth environments. However, in the current research situation, there are few reports on the response of the CBF gene to Begonia stress. Therefore, this experiment investigated a novel CBF TF gene, named MbCBF2, which was isolated from M. baccata seedlings. According to the subcellular localization results, the MbCBF2 protein was located in the nucleus. In addition, the expression level of MbCBF2 was higher in new leaves and roots under low-temperature and high-salt induction. After the introduction of MbCBF2 into Arabidopsis thaliana, the adaptability of transgenic A. thaliana to cold and high-salt environments was significantly enhanced. In addition, the high expression of MbCBF2 can also change many physiological indicators in transgenic A. thaliana, such as increased chlorophyll and proline content, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity, and reduced malondialdehyde (MDA) content. Therefore, it can be seen from the above results that MbCBF2 can positively regulate the response of A. thaliana to low-temperature and osmotic stress. In addition, MbCBF2 can also regulate the expression of its downstream genes in transgenic lines. It can not only positively regulate the expression of the downstream key genes AtCOR15a, AtERD10, AtRD29a/b and AtCOR6.6/47, related to cold stress at low temperatures, but can also positively regulate the expression of the downstream key genes AtNCED3, AtCAT1, AtP5CS, AtPIF1/4 and AtSnRK2.4, related to salt stress. That is, the overexpression of the MbCBF2 gene further improved the adaptability and tolerance of transgenic plants to low-temperature and high-salt environments.