The flavor profile of tea is influenced not only by different tea varieties but also by the surrounding soil environment. Recent studies have indicated the regulatory role of soil microbes residing in plant roots in nutrient uptake and metabolism. However, the impact of this regulatory mechanism on tea quality remains unclear. In this study, we showed that a consortium of microbes isolated from tea roots enhanced ammonia uptake and facilitated the synthesis of theanine, a key determinant of tea taste. Variations were observed in the composition of microbial populations colonizing tea roots and the rhizosphere across different seasons and tea varieties. By comparing the root microorganisms of the high-theanine tea variety Rougui with the low-theanine variety Maoxie, we identified a specific group of microbes that potentially modulate nitrogen metabolism, subsequently influencing the theanine levels in tea. Furthermore, we constructed a synthetic microbial community (SynCom) mirroring the microbe population composition found in Rougui roots. Remarkably, applying SynCom resulted in a significant increase in the theanine content of tea plants and imparted greater tolerance to nitrogen deficiency in Arabidopsis. Our study provides compelling evidence supporting the use of root microorganisms as functional microbial fertilizers to enhance tea quality.

White tea stored for various times have different flavors. However, the mechanism of flavor conversion remains elusive. Flavonoids and amino acids are two typical flavor components in tea. Herein, the contents of 46 flavonoids and 40 amino acids were measured in white tea (Shoumei) stored for 1, 3, 5 and 7 years, respectively. L-tryptophan, L-ornithine and L-theanine contribute to the refreshing taste of Shoumei 1 and 3. Quercetin, rutin and hesperidin contribute to aging charm and grain aroma of Shoumei 5 and 7. 306 bacterial OTUs and 268 fungal OTUs core microbiota existed in all samples. Interestingly, white teas contained higher richness of fungi than bacteria. The correlation analysis showed that the cooperation with bacteria and fungi may result in the flavonoids and amino acids composition changes in white teas during storage. Overall, this study provides new insights into flavor conversion of white tea during storage.

The formation of cell polarity is essential for many developmental processes such as polar cell growth and spatial patterning of cell division. A plant-specific ROP ( R h o -like GTPases from P lants) subfamily of conserved Rho GTPase plays a crucial role in the regulation of cell polarity. However, the functional study of ROPs in angiosperm is challenging because of their functional redundancy. The Marchantia polymorpha genome encodes a single ROP gene, Mp ROP , providing an excellent genetic system to study ROP-dependent signaling pathways. Mp rop knockout mutants exhibited rhizoid growth defects, and MpROP was localized at the tip of elongating rhizoids, establishing a role for MpROP in the control of polar cell growth and its functional conservation in plants. Furthermore, the Mp rop knockout mutant showed defects in the formation of meristem notches associated with disorganized cell division patterns. These results reveal a critical function of Mp ROP in the regulation of plant development. Interestingly, these phenotypes were complemented not only by Mp ROP but also Arabidopsis At ROP2 , supporting the conservation of ROP’s function among land plants. Our results demonstrate a great potential for M. polymorpha as a powerful genetic system for functional and mechanistic elucidation of ROP signaling pathways during plant development.

Leaves evolve shape diversity ranging from simple leaves with smooth margin to complicated shape with toothed/serrated, lobed and dissected leaves with leaflets. In the model plant Arabidopsis thaliana with simple leaves producing serrated margin, boundary regulatory factors CUP SHAPED COTYLEDON 2 (CUC2) and CUC3 play important roles in promoting leaf serration initiation and maintenance. Stem cell related WUSCHEL-RELATED HOMEOBOX1 (WOX1) and PRESSED FLOWER/WOX3 are also essential for leaf margin morphogenesis, but the role of WOX1 and PRS as well as the relationships between CUCs and WOXs on tooth development was unclear. In this study, we found that WOX1, but not PRS, prevents overproduction of tooth number and excessive tooth size by limiting CUC3 expression to a moderate level in a temporally regulated manner. We also revealed that BRASSINAZOLE RESISTANT 1 (BZR1), a known regulator for plant development including boundary regions, is involved in WOX1 negative regulation of tooth development by repressing CUC3 expression during the initiation/early stage of tooth development. WOX1 parallelly limits BZR1 and CUC3 expression from the late stage of the first 2 teeth, while restricts CUC3 activity in a BZR1 dependent manner from the initiation/early stage of subsequently developed teeth. This study uncovers a new mechanism for WOX1 in fine-tuning the leaf margin geometry.

The plant hormone auxin plays a key role to maintain root stem cell identity which is essential for root development. However, the molecular mechanism by which auxin regulates root distal stem cell (DSC) identity is not well understood. In this study, we revealed that the cell cycle factor DPa is a vital regulator in the maintenance of root DSC identity through multiple auxin signaling cascades. On the one hand, auxin positively regulates the transcription of DPa via AUXIN RESPONSE FACTOR 7 and ARF19. On the other hand, auxin enhances the protein stability of DPa through MITOGEN-ACTIVATED PROTEIN KINASE 3 (MPK3)/MPK6-mediated phosphorylation. Consistently, mutation of the identified three threonine residues (Thr ¹⁰ , Thr ²⁵ , and Thr ²²⁷ ) of DPa to nonphosphorylated form alanine (DPa ^3A ) highly decreased the phosphorylation level of DPa, which decreased its protein stability and affected the maintenance of root DSC identity. Taken together, this study provides insight into the molecular mechanism of how auxin regulates root distal stem cell identity through the dual regulations of DPa at both transcriptional and posttranslational levels.

The phytohormone auxin exerts control over remarkable developmental processes in plants. It moves from cell to cell, resulting in the creation of both extracellular auxin and intracellular auxin, which are recognized by distinct auxin receptors. These two auxin signaling systems govern different auxin responses while working together to regulate plant development. In this review, we outline the latest research advancements in unraveling these auxin signaling pathways, encompassing auxin perception and signaling transductions. We emphasize the interaction between extracellular auxin and intercellular auxin, which contributes to the intricate role of auxin in plant development.