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Changes in root system architecture are vital for plant adaptation to drought stress, yet the underlying molecular mechanisms of this process remain largely elusive. Here, FUSCA3 (FUS3), a B3 domain transcription factor isolated from Populus euphratica, was found to be an important gene of regulating lateral root (LR) development under drought stress. The expression of PeFUS3 was strongly induced by ABA and dehydration treatments. Overexpressing PeFUS3 in poplar 84 K (P. alba × P. glandulosa) positively regulated LR growth and enhanced drought tolerance, while the knockout lines, generated by the CRISPR/Cas9 system, displayed repressed LR growth and weakened drought tolerance. Further investigation demonstrated that PeFUS3 activated the expression of PIN2, PIN6a and AUX1, which were key genes involved in auxin transport, suggesting PeFUS3 modulated LR development under drought stress through auxin signalling. Moreover, PeFUS3 directly upregulated PePYL3 expression, and overexpressing PePYL3 poplar lines exhibited significantly increased drought resistance. In addition, PeABF2, an ABA responsive transcription factor, interacted with PeFUS3 and activated its transcription, indicating PeFUS3 was involved in ABA signalling pathway. Taken together, PeFUS3 is a key regulator, maintaining root growth of poplar by modulating the crosstalk of auxin and ABA signalling under drought stress. Summary statement: PeFUS3, a B3 domain transcription factor, promotes lateral root (LR) development under drought stress via modulating the crosstalk of auxin and ABA signalling. These findings unravel a novel molecular mechanism of balancing root growth and drought resistance under drought stress in Populus. [ABSTRACT FROM AUTHOR]

The standards system for supporting high-quality development is based on the development concept of “innovation, coordination, green, openness, and sharing” and supports the all-round, high-quality development of China’s economy, society, and ecology. Conducting strategic research on this standards system plays a basic and leading role in promoting economic development, ecological environment quality, and social governance level, and is significant for meeting people’s needs for a better life. In this article, we analyze the concept of high-quality development as well as the connotation and characteristics of the standards system for supporting high-quality development, and study the difference between the high-quality development standards system and existing systems. Moreover, this study presents the main directions and implementation paths for the standards system by 2025 and 2035, focusing on agriculture, manufacturing, services, social governance, ecological civilization, and other key areas. Furthermore, we propose corresponding countermeasures in aspects of top level design, standardization policies, standardization capability improvement, and standardization personnel training, hoping to provide references for the development of the aforementioned key areas and for the decision making of relevant government departments.

Summary: MicroRNAs are essential in plant development and stress resistance, but their specific roles in drought stress require further investigation.Here, we have uncovered that a Populus‐specific microRNAs (miRNA), miR6445, targeting NAC (NAM, ATAF, and CUC) family genes, is involved in regulating drought tolerance of poplar.The expression level of miR6445 was significantly upregulated under drought stress; concomitantly, seven targeted NAC genes showed significant downregulation. Silencing the expression of miR6445 by short tandem target mimic technology significantly decreased the drought tolerance in poplar. Furthermore, 5′ RACE experiments confirmed that miR6445 directly targeted NAC029. The overexpression lines of PtrNAC029 (OE‐NAC029) showed increased sensitivity to drought compared with knockout lines (Crispr‐NAC029), consistent with the drought‐sensitive phenotype observed in miR6445‐silenced strains. PtrNAC029 was further verified to directly bind to the promoters of glutathione S‐transferase U23 (GSTU23) and inhibit its expression. Both Crispr‐NAC029 and PtrGSTU23 overexpressing plants showed higher levels of PtrGSTU23 transcript and GST activity while accumulating less reactive oxygen species (ROS). Moreover, poplars overexpressing GSTU23 demonstrated enhanced drought tolerance.Taken together, our research reveals the crucial role of the miR6445‐NAC029‐GSTU23 module in enhancing poplar drought tolerance by regulating ROS homeostasis. This finding provides new molecular targets for improving the drought resistance of trees. [ABSTRACT FROM AUTHOR]