Boosting Apple Water Efficiency and Strength by Regulating Key Plant Enzyme

Greg Howard
24th July, 2024

Boosting Apple Water Efficiency and Strength by Regulating Key Plant Enzyme

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Northwest A&F University found that overexpressing the MdMRLK2 gene in apple trees improves water use efficiency (WUE) under drought conditions
  • The modified apple trees showed higher photosynthetic capacity, increased antioxidant enzyme activities, greater biomass, and improved root activity and water potential
  • The MdMRLK2 gene interacts with and modifies the MdCCR1 enzyme, enhancing lignin synthesis, which strengthens plant cell walls and improves drought tolerance
Water use efficiency (WUE) is a critical factor for the survival and productivity of apple trees, especially under the increasing threat of climate change. A recent study conducted by researchers at Northwest A&F University has identified a novel role for the receptor-like kinase FERONIA in enhancing WUE in apple trees under long-term water deficit conditions[1]. This discovery holds significant implications for improving apple tree resilience to drought. In this study, the researchers focused on the apple FERONIA receptor kinase gene, MdMRLK2. They found that overexpressing this gene in apple trees (referred to as 35S::MdMRLK2 plants) resulted in enhanced WUE compared to wild-type (WT) plants under drought conditions. The 35S::MdMRLK2 plants exhibited several advantageous traits, including higher photosynthetic capacity, increased antioxidant enzyme activities, greater biomass accumulation, and improved root activity and water potential. One of the key findings of the study is the interaction between MdMRLK2 and cinnamoyl-CoA reductase 1 (MdCCR1), an enzyme crucial for lignin synthesis. The researchers discovered that MdMRLK2 physically interacts with and phosphorylates MdCCR1 at position Ser260. This interaction likely contributes to increased vessel density, vascular cylinder area, and lignin content in the 35S::MdMRLK2 plants under drought conditions. Lignin is a complex polymer that strengthens and waterproofs plant cell walls, playing a vital role in plant drought tolerance[2][3]. The study builds on previous research that has highlighted the importance of lignin in drought tolerance. For instance, a study on rice demonstrated that overexpressing a gene involved in lignin biosynthesis (OsCCR10) improved drought tolerance by increasing lignin content in roots[2]. Similarly, the current study on apple trees suggests that enhancing lignin synthesis through the interaction of MdMRLK2 and MdCCR1 can improve WUE and drought resilience. Moreover, the findings align with earlier research on the importance of root traits in drought adaptability. A study on wheat showed that re-introducing ancestral alleles from wild emmer wheat led to greater root elongation and higher water uptake from deeper soil layers, resulting in improved grain yield under drought conditions[4]. Similarly, the increased root activity observed in the 35S::MdMRLK2 apple plants likely contributes to their enhanced WUE and overall drought tolerance. The researchers employed a variety of methods to arrive at their conclusions. They used genetic engineering to overexpress MdMRLK2 in apple plants and conducted drought treatment experiments to compare the performance of 35S::MdMRLK2 plants with WT plants. They measured photosynthetic capacity, antioxidant enzyme activities, biomass accumulation, root activity, and water potential. Additionally, they performed protein interaction assays to investigate the physical interaction between MdMRLK2 and MdCCR1 and examined lignin content and vascular tissue characteristics. In summary, this study reveals a novel function of the apple FERONIA receptor kinase gene, MdMRLK2, in regulating WUE under water deficit conditions. By enhancing photosynthetic capacity, antioxidant enzyme activities, root activity, and lignin synthesis, overexpressing MdMRLK2 improves apple tree resilience to drought. These findings contribute to our understanding of plant stress responses and offer potential strategies for improving crop resilience in the face of climate change.

AgricultureBiochemPlant Science

References

Main Study

1) Overexpression of FERONIA receptor kinase MdMRLK2 regulates lignin accumulation and enhances water use efficiency in apple under long-term water deficit condition.

Published 23rd July, 2024

https://doi.org/10.1111/tpj.16938

Related Studies

2) Transcriptional activation of rice CINNAMOYL-CoA REDUCTASE 10 by OsNAC5, contributes to drought tolerance by modulating lignin accumulation in roots.

https://doi.org/10.1111/pbi.13752

3) The cell biology of lignification in higher plants.

https://doi.org/10.1093/aob/mcv046

4) Stress-induced deeper rooting introgression enhances wheat yield under terminal drought.

https://doi.org/10.1093/jxb/erad059


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