The maize transcription factor CCT regulates drought tolerance by interacting with Fra a 1, E3 ligase WIPF2, and auxin response factor Aux/IAA8.

Plants are commonly exposed to abiotic stressors, which can affect their growth, productivity, and quality. Previously, the maize transcription factor ZmCCT was shown to be involved in the photoperiod response, delayed flowering, and quantitative resistance to Gibberella stalk rot. In this study, we demonstrate that ZmCCT can regulate plant responses to drought. ZmCCT physically interacted with ZmFra a 1, ZmWIPF2, and ZmAux/IAA8, which localized to the cell membrane, cytoplasm, and nucleus, respectively, both in vitro and in vivo in a yeast two-hybrid screen in response to abiotic stress. Notably, ZmCCT recruits ZmWIPF2 to the nucleus, which has strong E3 self-ubiquitination activity dependent on its RING-H2 finger domain in vitro. When treated with higher indole-3-acetic acid/abscisic acid ratios, the height and root length of Y331-ΔTE maize plants increased. Y331-ΔTE plants exhibited increased responses to exogenously applied auxin or ABA compared to Y331 plants, indicating that ZmCCT may be a negative regulator of ABA signalling in maize. In vivo, ZmCCT promoted indole-3-acetic acid biosynthesis in ZmCCT-overexpressing Arabidopsis. RNA-sequencing and DNA affinity purification-sequencing analyses showed that ZmCCT can regulate the expression of ZmRD17, ZmAFP3, ZmPP2C, and ZmARR16 under drought. Our findings provide a detailed overview of the molecular mechanism controlling ZmCCT functions and highlight that ZmCCT has multiple roles in promoting abiotic stress tolerance.

MoJMJD6, a Nuclear Protein, Regulates Conidial Germination and Appressorium Formation at the Early Stage of Pathogenesis in Magnaporthe oryzae.

In plant-pathogen interactions, Magnaporthe oryzae causes blast disease on more than 50 species of 14 monocot plants, including important crops such as rice, millet, and most 15 recently wheat. M. oryzae is a model fungus for studying plant-microbe interaction, and the main source for fungal pathogenesis in the field. Here we report that MoJMJD6 is required for conidium germination and appressorium formation in M. oryzae. We obtained MoJMJD6 mutants (ΔMojmjd6) using a target gene replacement strategy. The MoJMD6 deletion mutants were delayed for conidium germination, glycogen, and lipid droplets utilization and consequently had decreased virulence. In the ΔMojmjd6 null mutants, global histone methyltransferase modifications (H3K4me3, H3K9me3, H3K27me3, and H3K36me2/3) of the genome were unaffected. Taken together, our results indicated that MoJMJD6 function as a nuclear protein which plays an important role in conidium germination and appressorium formation in the M. oryzae. Our work provides insights into MoJMJD6-mediated regulation in the early stage of pathogenesis in plant fungi.