Search

The Cys2His2 (C2H2)-type zinc-finger protein (ZFP) family, which includes 176 members in Arabidopsis thaliana, is one of the largest families of putative transcription factors in plants. Of the Arabidopsis ZFP members, only 33 members are conserved in other eukaryotes, with 143 considered to be plant specific. C2H2-type ZFPs have been extensively studied and have been shown to play important roles in plant development and environmental stress responses by transcriptional regulation. The ethylene-responsive element binding-factor-associated amphiphilic repression (EAR) domain (GCC box) has been found to have a critical role in the tolerance response to abiotic stress. Many of the plant ZFPs containing the EAR domain, such as AZF1/2/3, ZAT7, ZAT10, and ZAT12, have been shown to function as transcriptional repressors. In this review, we mainly focus on the C1-2i subclass of C2H2 ZFPs and summarize the latest research into their roles in various stress responses. The role of C2H2-type ZFPs in response to the abiotic and biotic stress signaling network is not well explained, and amongst them, C1-2i is one of the better-characterized classifications in response to environmental stresses. These studies of the C1-2i subclass ought to furnish the basis for future studies to discover the pathways and receptors concerned in stress defense. Research has implied possible protein-protein interactions between members of C1-2i under various stresses, for which we have proposed a hypothetical model.

Zinc finger homeodomain (ZF-HD) transcription factors play significant roles in plant growth and responses to environmental stresses. In this study, 32 ZF-HD genes identified in the tobacco (Nicotiana tabacum L.) genome were divided into six groups according to phylogenetic analysis with Arabidopsis and tomato ZF-HD members. An examination of gene structures and conserved motifs revealed the relatively conserved exon/intron structures and motif organization within each subgroup. In addition, various stress-related elements are found in the promoter region of these genes. The expression profiling analysis revealed that NtZF-HD genes expressed in different tissues and could be induced by several abiotic stresses. Notably, NtZF-HD21 was highly expressed in response to the drought treatments. Subcellular localization analysis and a virus-induced gene silencing (VIGS) experiment were performed to investigate the potential functions of NtZF-HD21. The subcellular localization indicated that NtZF-HD21 is a nuclear protein. Furthermore, gene silencing of the NtZF-HD21 gene reduced the drought resistance of tobacco. These findings provide insights for further biological functional analyses of the NtZF-HD genes in tobacco.

This review archives the achievements made in the last two decades and presents a brief outline of some significant factors influencing the Agrobacterium-mediated transformation of Sorghum bicolor. Recently, progress in successful transformation has been made for this particular monocot crop through direct DNA delivery method and indirect method via Agrobacterium. However, lower transformation rate still proved to be a bottleneck in genetic modification of sorghum. An efficient Agrobacterium transformation system could be attained by optimizing the preliminary assays, comprising of explant source, growth media, antibiotics, Agrobacterium strains and agro-infection response of callus. The selection of competent strains for genetic transformation is also one of the key factors of consideration. Successful transformation is highly dependent on genome configuration of selected cultivar, where non-tannin genotype proved the best suited. Immature embryos from the field source have higher inherent adaptation chances than that of the greenhouse source. A higher concentration of Agrobacterium may damage the explant source. Utilization of anti-necrotic treatments and optimized tissue culture timeframe are the adequate strategies to lower down the effect of phenolic compounds. Appropriate selection of culture media vessels at different stages of tissue culture may also assist in a constructive manner. In conclusion, some aspects such as culture environment with medium composition, explant sources, and genotypes play an indispensable role in successful Agrobacterium-mediated sorghum transformation system.

E3 ubiquitin ligases are the most expanded components of the ubiquitin proteasome system (UPS). They mediate the recognition of substrates and later transfer the ubiquitin (Ub) of the system. Really Interesting New Gene (RING) finger proteins characterized by the RING domain, which contains 40–60 residues, are thought to be E3 ubiquitin ligase. RING-finger proteins play significant roles in plant growth, stress resistance, and signal transduction. In this study, we mainly describe the structural characteristics, classifications, and subcellular localizations of RING-finger proteins, as well the physiological processes of RING-finger proteins in plant growth and development. We also summarize the functions of plant RING-finger proteins in plant stress resistance. Finally, further research on plant RING-finger proteins is suggested, thereby establishing a strong foundation for the future study of plant RING-finger proteins.