| Title | The mitochondrial DnaJA protein LMA1 regulates reactive oxygen species homeostasis and anthocyanin biosynthesis in Medicago truncatula |
| Author | Wu, Qing |
| Publication | PLANT DIVERSITY |
| Year | 2026 |
| Volume | 48 |
| Issue | 3 |
| Corresponding Author | Chen, JH; Zhao, BL |
| Abstract | Reactive oxygen species (ROS) play an important role as a key signal in plant adaptation to environment stresses, and the stress-induced anthocyanins accumulation are also critical for plant adaptation; however, molecular mechanisms coordinating these processes remain poorly understood in legumes. Here, we identified a novel player in the ROS-anthocyanin crosstalk signal in the model plant Medicago truncatula. Using the forward-genetic approach, we isolated a leaves with more ROS and anthocyanin1 (lma1) mutant, which exhibits ROS hyperaccumulation in its leaves. The LMA1 gene was then cloned by a whole genome resequencing assay and was found to encode a conserved mitochondria-localized type A DnaJ (DnaJA) protein. Loss of LMA1 function additionally induced ectopic anthocyanin accumulation in their small leaves, supported by upregulation of genes involved in the anthocyanin biosynthesis. The transcriptomic analysis also uncovered the mitochondrial dysfunction in lma1-1, as evidenced by further ultrastructural and physiological analyses showing severe mitochondrial defects and reduced activity of mitochondrial respiratory chain complex I in lma1. Treatment with exogenous H 2 O 2 and the ROS scavenger N, N '-dimethylthiourea (DMTU) significantly exacerbated and inhibited ROS as well as anthocyanin accumulation in lma1 mutants, respectively, correlating with the expression dynamics of anthocyanin biosynthetic genes. Overall, we establish that LMA1 maintains mitochondrial integrity to influence ROS and anthocyanin accumulation, revealing a potential mechanism by which DnaJA proteins orchestrate the ROS-driven anthocyanin homeostasis in plants. (c) 2026 Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). |
