On February 10, 2026, the research team led by Professor Ning Xu from the School of Life Sciences, Guizhou University, published a research article entitled “Auxin pathway-mediated enhancement of root architecture and osmotic stress tolerance by OsZFP350 improves rice yield” in Plant Stress.
During the research process, germinated wild-type Zhonghua 11 (ZH11) and OsZFP350 transgenic lines (with shoot lengths of approximately 1 mm) were inoculated onto 1/2 Murashige and Skoog (MS) medium. Subsequently, the plants were cultured in a JIUPO Walk-in Chamber (Fujian Jiupo Biotechnology Co., Ltd.) under controlled conditions: a temperature of 30°C and a 16 h light/8 h dark photoperiod. After cultivation, phenotypic evaluation was conducted. This study aimed to elucidate the function and molecular mechanism of OsZFP350, providing potential targets for breeding rice varieties with enhanced stress resistance and high yield.
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Rice is one of the most important staple crops worldwide. Its root system architecture (RSA) directly determines the efficiency of water and nutrient uptake and serves as a critical organ for responding to osmotic stresses such as drought and salinity. For a long time, how root development and stress adaptation responses are coordinately regulated by the same gene has remained a key scientific question in rice stress-resistant breeding. In this study, OsZFP350 was investigated through multi-level analyses ranging from molecular and cellular mechanisms to whole-plant and field-level validation, revealing its essential role as an upstream regulator of the auxin pathway.
The study first identified through expression pattern analysis that OsZFP350 exhibits root-specific expression in rice, and its expression level is significantly upregulated under osmotic stress conditions including salt stress, drought stress, and high temperature stress, suggesting that this gene plays an important role in root stress responses.
By generating OsZFP350 overexpression lines and loss-of-function mutants, researchers discovered that compared with wild-type plants, OsZFP350-overexpressing plants displayed longer primary roots, significantly increased numbers of adventitious roots and lateral roots, higher root hair density, and an overall improved root system architecture. In contrast, mutant plants exhibited opposite phenotypes, including shorter roots, fewer lateral roots, and impaired root hair development.
Figure 1. Expression pattern analysis of the OsZFP350 gene
At the molecular mechanism level, this study demonstrated that OsZFP350 functions through comprehensive activation of the auxin (IAA) pathway. On one hand, it enhances the expression of auxin biosynthesis-related genes, such as OsYUCs and OsTAR2, thereby promoting endogenous auxin production in roots. On the other hand, it increases the expression of polar auxin transport genes, including OsPIN1a and OsPIN1b, facilitating effective auxin accumulation in root tips and lateral root primordia. Meanwhile, it regulates downstream signaling genes such as OsIAA9 and OsIAA23, further amplifying auxin signaling and coordinately promoting root cell division, elongation, and differentiation.
Exogenous auxin supplementation experiments demonstrated that root developmental defects in mutants could be largely restored through IAA treatment, further confirming that the biological function of OsZFP350 is highly dependent on the auxin pathway.
Figure 2. Comparison of root phenotypes among wild-type, OsZFP350 overexpression lines, and gene knockout mutants
Under osmotic stress conditions (drought and high salinity treatments), OsZFP350 overexpression lines exhibited stronger stress tolerance. They showed higher seed germination rates, reduced root damage, and significantly improved survival rates compared with wild-type plants. In contrast, mutant plants were highly sensitive to stress, with severely inhibited root growth.
The researchers proposed that OsZFP350 maintains root cell activity, osmotic balance, and adaptive growth plasticity under stress conditions through the auxin pathway, enabling plants to maintain efficient water and nutrient uptake under drought or high-salt environments.
Figure 3. OsZFP350 regulates root growth through mediation of the auxin signaling pathway
Most importantly, field trial results demonstrated that under normal cultivation conditions, OsZFP350-overexpressing lines exhibited significantly improved root biomass, root length, root surface area, and root-order connectivity during maturity.
Regarding agronomic traits, panicle length increased by approximately 12%, thousand-grain weight increased by approximately 15%, grain length-to-width ratio increased by approximately 9%, and seed-setting rate improved, ultimately resulting in stable increases in both individual plant yield and plot yield.
In contrast, mutants exhibited reduced seed-setting rates and significantly decreased yield due to impaired root development and reduced pollen fertility.
Figure 4. Improvement of field yield
In conclusion, this study systematically elucidated for the first time the complete regulatory pathway of OsZFP350–auxin pathway–root system architecture–osmotic stress tolerance–yield improvement. The findings demonstrate that OsZFP350 is an important genetic target that simultaneously improves rice root architecture and stress resistance, ultimately enhancing yield.
This research not only deepens our understanding of how plant hormones regulate root development and environmental adaptation mechanisms but also provides directly applicable genetic resources and theoretical foundations for molecular breeding of stress-resistant and high-yielding rice varieties. It carries significant implications for ensuring global food security under increasingly frequent extreme climate conditions.