Seed desiccation is a key physiological process during plant seed maturation, directly affecting seed moisture content, storage, and quality. In agricultural practice, the kernel dehydration rate (KDR) is a critical determinant of seed water content at harvest and seed quality for mechanical harvesting. Over the past decades, although physiological changes in transcriptome and hormone levels have been linked to seed dehydration, little progress for underlying mechanisms has been achieved. A recent study identified a QTL located in a non-coding region, named qKDR1, which regulates the dehydration rate during maize seed maturation. By recruiting the transcription factors ZmMYBST1 and ZmMYBR43, it suppresses the transcription of the micropeptide-encoding gene RPG upstream of qKDR1, leading to reduced expression of RPG. The encoded micropeptide, microRPG1, regulates the KDR through the ethylene signaling pathway, highlighting its potential in crop breeding and agricultural practices. This study advances our understanding of the molecular mechanisms underlying seed desiccation and provides theoretical support for breeding crops with faster KDR and improved storage qualities.

Strigolactone (SL) is a novel plant hormone that regulates important growth and developmental processes such as plant branching. In rice, the SL receptor D14 perceives SL signals, binds with the F-box protein D3, and recruits the transcriptional repressor D53, inducing the ubiquitination and degradation of D53, thereby triggering signal transduction and inhibiting tillering. A recent study discovered that nitrogen limitation induces SL biosynthesis in rice to activate the receptor D14, triggering SL signal transduction. Concurrently, nitrogen limitation also induces phosphorylation of the N-terminal disordered region (NTD) of D14, reducing the ubiquitination and degradation of receptor D14, thereby further enhancing SL perception. Through these two synergistic mechanisms, nitrogen limitation stimulates SL signal transduction, strongly inhibiting tillering and enabling rice to adapt to low nitrogen stress conditions. The study also found that the D14-D3 interaction induced by SL promotes the ubiquitination and degradation of D14, thereby mediating the termination of SL signal perception. These significant findings elucidate the mechanisms of activation and termination of SL perception in rice, revealing the crucial regulatory role of SL signals in controlling rice tillering under low nitrogen stress. This would provide key insights into plant adaptation to nutrient scarcity and guide the precise improvement of crop architecture and molecular breeding of rice for reduced fertilizer use and increased yield.

Cryptochromes (CRYs) are blue light receptors that regulate various plant responses. CRYs exist in the dark as an inactive monomer, which absorbs photons and undergo conformational changes and oligomerization. Light alters the affinity between CRYs and interacting proteins, thereby regulating the transcription or stability of photoresponsive proteins to modulate plant growth and development. A recent study has discovered a sophisticated mechanism of CRY2 function, which is not only ‘activated’ by blue light but also by dark signals, thus constructing a more energy-efficient mode of light and dark signal dependent photoreceptor signaling. The authors found that CRY2 can inhibit cell division in root meristematic tissue even in the dark, regulate root elongation and growth, and control the expression of a large number of genes. FL1 and FL3 bind to the chromatin of cell division genes to promote their transcription. It is interesting that only the CRY2 monomer in the dark interacts with FL1/FL3, thereby inhibiting FL1/FL3 to promote root elongation, while blue light releases this inhibitory effect. This discovery reshapes people’s understanding of light receptors, and provides a new perspective for understanding plant perception and response to different signals to regulate growth and adaptability. Moreover, it is highly enlightening for a deeper understanding of sophisticated gene regulation.

Plant immune receptors such as the rice OsCERK1 protein is crucial for sensing immunogenic signal from pathogenic microbes and activate defenses. The immune activity of these immune receptors, however, must be tightly controlled to ensure normal growth when the pathogen is not present. How plants properly manage the speed of immune activation and stringent control is important for the survival of plants in a complex environment. A recent research discovered an E3 ligase, OsCIE1, that acts as a molecular brake controlling OsCERK1 activation in the absence of the immunogenic signal chitin. OsCIE1 inhibits the kinase activity of OsCERK1 by ubiquitination, thereby negatively regulating immunity. Upon perception of chitin, OsCERK1 phosphorylates OsCIE1 to inhibit the E3 ligase activity, thereby releasing the brake and allowing robust activation of defenses.

Living organisms are often exposed to a wide range of biotic and abiotic stresses that cause severe wounding, leading to partial or complete organ loss. Being sessile, plants have evolved powerful regenerative capabilities to adapt to the environment. Wounding is a prerequisite for plant regeneration, the local wound signals that trigger regenerative responses remained unknown for centuries. A recent study has identified a small peptide, REF1, that regulates local wound responses and regeneration capabilities in plants. The study found that REF1 and its receptor PORK1 can promote plant regeneration by activating WIND1, a master regulator of wound-induced cellular reprogramming in plants. Crucially, exogenous application of the REF1 peptide can improve the regeneration efficiency of several crops to varying degrees. This discovery not only provides a new perspective on the molecular mechanisms of plant injury responses and regene- ration, but also offers potential application strategies for enhancing the regenerative capacity and transformation efficiency of crops.

The numerous flowering genes that have been identified in different plants play a crucial role in determining whether a plant is annual or perennial. However, the evolutionary mechanism by which these flowering genes drive the transition between annual and perennial life history strategies in Brassicaceae plants remains poorly understood. A recent study focused on natural variations in different genera of Brassicaceae. They identified three closely related MADS-box transcription factor genes, namely FLC, FLM, and MAF, and elucidated their molecular mechanisms associated with the transition between annual and perennial behavior. Their findings suggest that the life-history strategy in Brassicaceae plants (i.e., the conversion between perennial, biennial, and annual behavior) is a continuum determined by the dosage of FLC-like MADS-box genes. The study elucidates the evolutionary mechanisms and trajectories underlying the reciprocal conversion of life history strategies from annual to perennial in Brassicaceae, providing a theoretical foundation for breeding perennial rapeseed varieties and offering insights for Brassicaceae crops improved towards perennial grain.