Molecular Plant最新文献

Rice bacterial blight is a devastating disease worldwide, causing significant yield losses. Understanding how plants defend against microbial infection is critical for sustainable crop production. In this study, we show that ALEX1, a previously identified pathogen-induced long noncoding RNA, localizes to the nucleus and directly binds AUXIN RESPONSE FACTOR 3 (ARF3). We showed that ARF3 forms the condensates in the nucleus via its intrinsically disordered middle region (MR), and that these ARF3 condensates display solid-like properties. We further revealed that ALEX1 directly binds the MR of ARF3 to regulate ARF3 condensate dynamics and promote ARF3 homodimerization. The dispersed, dimeric form of ARF3, referred to as its functional phase state, enhances its ability to transcriptionally repress the expression of downstream target genes such as JAZ13, thereby modulating the jasmonic acid signaling pathway and enhancing pathogen resistance in rice. Collectively, this study reveals the role of a long noncoding RNA in regulating protein condensation and complex assembly, thus contributing to plant pathogen resistance.

Photoperiod- and thermo-sensitive genic male sterile (P/TGMS) lines display male sterility under high-temperature/long-day light conditions and male fertility under low-temperature/short-day light conditions. P/TGMS lines are the fundamental basis for the two-line hybrid breeding, which has notably increased the yield potential and grain quality of rice cultivars. In this review, we focus on the research progress on photoperiod- and thermo-sensitive genic male sterility in plants. The essence of P/TGMS line is their ability to produce viable pollen under varying conditions. We overview the processes involved in anther and pollen development, as well as the molecular, cellular, and genetic mechanisms underlying P/TGMS in Arabidopsis, rice, and other crops. Slow development has been identified as a common mechanism of P/TGMS fertility restoration in both Arabidopsis and rice, while reactive oxygen species homeostasis has been implicated in rice P/TGMS. Furthermore, we discuss the prospective applications of P/TGMS and potential solutions to the challenges in this field. This review deepens the understanding of the mechanisms underlying P/TGMS and its utilization in two-line hybrid breeding across diverse crops.

Nitric oxide (NO) is a crucial signaling molecule that regulates a wide range of metabolic pathways in different strata of organisms. In plants, nitrate reductase (NR) is a key enzyme for NO biosynthesis. There are two NR-encoding genes in Arabidopsis genome, NIA1 and NIA2, which are precisely regulated and expressed in a tissue-specific manner. In this study, we found that the natural antisense transcript as-NIA1, transcribed from the 3' UTR of NIA1, stabilizes NIA1 mRNA to maintain its circadian oscillation in plants grown under the light/dark cycle. Importantly, as-NIA1-dependent NIA1 mRNA stability is indispensable for NIA1-mediated NO biosynthesis in guard cells and natural stomatal closure. Moreover, we revealed that polypyrimidine tract-binding 3 (PTB3) regulates the stabilization of NIA1 mRNA by directly binding to UC-rich elements of as-NIA1. We further found that MTA deposits N⁶-methyladenosine (m⁶A) on as-NIA1, facilitating the as-NIA1-PTB3 interaction in vivo, in agreement with RNA structure prediction in that m⁶A-mediated structural alterations expose the UC-rich elements to enhance the accessibility of PTB3. Taken together, these findings reveal a novel molecular mechanism by which plants precisely manipulate NO biosynthesis to modulate light/dark-regulated stomatal movement, highlighting the coupling of RNA epigenetic modifications and structures shaping RNA-protein interactions in the regulation of hormone biosynthesis.

This study uncovers the role of H4K8hib as an active epigenetic mark in rice that positively correlates with gene expression and enhances immune responses. Furthermore, HDA705 was identified as the key enzyme regulating H4K8hib. Mutation of HDA705 led to hyper-H4K8hib, which in turn activated the expression of defense-related genes and enhanced rice resistance to pathogens.

Trimethylation of histone H3K4 (H3K4me3) is widely distributed at numerous actively transcribed protein-coding genes throughout the genome. However, the interplay between H3K4me3 and other chromatin modifications in plants remains poorly understood. In this study, we show that the Arabidopsis thaliana ALFIN-LIKE (AL) proteins contain a C-terminal PHD finger capable of binding to H3K4me3 and a PHD-associated AL (PAL) domain that interacts with components of the Polycomb repressive complex 1, thereby facilitating H2A ubiquitination (H2Aub) at H3K4me3-enriched genes throughout the genome. Furthermore, we demonstrate that loss of function of SDG2, encoding a key histone H3K4 methyltransferase, leads to a reduction in H3K4me3 level, which subsequently causes a genome-wide decrease in H2Aub, revealing a strong association between H3K4me3 and H2Aub. Finally, we discover that the PAL domain of AL proteins interacts with various other chromatin-related proteins or complexes, including those involved in regulating H2A.Z deposition, H3K27me3 demethylation, histone deacetylation, and chromatin accessibility. Our genome-wide analysis suggests that the AL proteins play a crucial role in coordinating H3K4me3 with multiple other chromatin modifications across the genome.