Conditional and tissue-specific approaches to dissect essential mechanisms in plant development

CRISPR-Cas9 and beyond: identifying target genes for developing disease-resistant plants

Throughout the history of crop domestication, desirable traits have been selected in agricultural products. However, such selection often leads to crops and vegetables with weaker vitality and viability than their wild ancestors when exposed to adverse environmental conditions. Considering the increasing human population and climate change challenges, it is crucial to enhance crop quality and quantity. Accordingly, the identification and utilization of diverse genetic resources are imperative for developing disease-resistant plants that can withstand unexpected epidemics of plant diseases. In this review, we provide a brief overview of recent progress in genome-editing technologies, including zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) technologies. In particular, we classify disease-resistant mutants of Arabidopsis thaliana and several crop plants based on the roles or functions of the mutated genes in plant immunity and suggest potential target genes for molecular breeding of genome-edited disease-resistant plants. Genome-editing technologies are resilient tools for sustainable development and promising solutions for coping with climate change and population increases.

The emerging functions of mini zinc finger (MIF) microproteins in seed plants: A minireview

Mini zinc fingers constitute a class of microproteins that appeared early in evolution and expanded in seeds plants. In this review, the phylogenetic history, the functions and the mode of action of Mini zinc fingers in plants are reported and discussed. It appears that mini zinc fingers play an important role in the control of plant development. They are involved in the control of cell division and expansion, in the switch between the determinate/indeterminate state of the meristems and in the regulation of vegetative growth and floral organ development. Their biochemical mode of action seems to be diverse. In some studies, it has been reported that mini zinc fingers can directly bind to DNA and activate target gene expression, whereas other studies have shown that they can interact with and inhibit the activity of specific zinc finger homeodomain transcription factors or act as adaptor proteins necessary to aggregate polymeric protein complexes corresponding to chromatin remodelling factors negatively regulating the expression of specific genes. The diversity of mode of action for mini zinc finger microproteins suggests a wider range of biological functions than what has been that described in the literature thus far, and their involvement in the response to biotic and abiotic stresses should be further investigated in future studies.

Expanding the application of anti-CRISPR proteins in plants for tunable genome editing

Anti-CRISPR proteins are very efficient for inhibiting CRISPR/Cas9-based genome editing tools in both herbaceous and woody plant species.

Zinc Finger-Homeodomain and Mini Zinc Finger proteins are key players in plant growth and responses to environmental stresses

The ZINC FINGER-HOMEODOMAIN (ZHD) protein family is a plant-specific family of transcription factors containing two conserved motifs: a non-canonical C5H3 zinc finger domain (ZF) and a DNA-binding homeodomain (HD). The MINI ZINC FINGER (MIF) proteins belong to this family, but were possibly derived from the ZHDs by losing the HD. Information regarding the function of ZHD and MIF proteins is scarce. However, different studies have shown that ZHD/MIF proteins play important roles not only in plant growth and development, but also in response to environmental stresses, including drought and pathogen attack. Here we review recent advances relative to ZHD/MIF functions in multiple species, to provide new insights into the diverse roles of these transcription factors in plants. Their mechanism of action in relation to their ability to interact with other proteins and DNA is also discussed. We then propose directions for future studies to understand better their important roles and pinpoint strategies for potential applications in crop improvement.

Plant proteostasis: a proven and promising target for crop improvement

The Green Revolution of the 1960s accomplished dramatic increases in crop yields through genetic improvement, chemical fertilisers, irrigation, and mechanisation. However, the current trajectory of population growth, against a backdrop of climate change and geopolitical unrest, predicts that agricultural production will be insufficient to ensure global food security in the next three decades. Improvements to crops that go beyond incremental gains are urgently needed. Plant biology has also undergone a revolution in recent years, through the development and application of powerful technologies including genome sequencing, a pantheon of 'omics techniques, precise genome editing, and step changes in structural biology and microscopy. Proteostasis - the collective processes that control the protein complement of the cell, comprising synthesis, modification, localisation, and degradation - is a field that has benefitted from these advances. This special issue presents a selection of the latest research in this vibrant field, with a particular focus on protein degradation. In the current article, we highlight the diverse and widespread contributions of plant proteostasis to agronomic traits, suggest opportunities and strategies to manipulate different elements of proteostatic mechanisms for crop improvement, and discuss the challenges involved in bringing these ideas into practice.