Key Genes Regulate Leaf Rolling and Drought Response in Rice

Jenn Hoskins
28th July, 2024

Key Genes Regulate Leaf Rolling and Drought Response in Rice

Image Source: Natural Science News, 2024

Key Findings

  • The study by the Chinese Academy of Sciences focused on rice plants and how the ROC1 gene affects leaf rolling and drought response
  • Overexpressing ROC1 in rice leads to smaller bulliform cells and inward-rolled leaves, while knocking out ROC1 results in larger bulliform cells and outward-rolled leaves
  • ROC1 knockout plants are more sensitive to drought, and this sensitivity increases when both ROC1 and ROC8 are knocked out
Leaf morphology significantly impacts rice crop yield, and one key factor influencing leaf shape is the alteration in bulliform cells. A recent study by researchers at the Chinese Academy of Sciences has shed light on how the HD-ZIP IV family of transcription factors, particularly ROC1, regulates leaf rolling and drought response in rice[1]. Bulliform cells are specialized cells in the leaves of grasses like rice that play a role in leaf rolling, which can affect water retention and photosynthesis. Leaf rolling can be advantageous under certain conditions, such as moderate rolling increasing photosynthesis and grain yield[2]. However, extreme rolling can be detrimental, particularly under drought conditions, as it affects water transport within the leaf and overall plant health[3]. The study focused on ROC1, one of the nine ROC genes encoding HD-ZIP IV family transcription factors in rice. ROC1 is highly expressed in rice leaves, and its overexpression results in smaller bulliform cells, causing the leaves to roll adaxially (inward). Conversely, knocking out ROC1 using the Crispr-Cas9 system led to larger bulliform cells and abaxially (outward) rolled leaves. This knockout also made the plants more sensitive to drought. Interestingly, ROC1 can form homodimers (pairs of identical molecules) or heterodimers (pairs of different molecules) with other HD-ZIP IV family members, specifically ROC5 and ROC8. The study found that double knockout plants for both ROC1 and ROC8 exhibited more severe abaxial leaf rolling and increased drought sensitivity compared to plants with only ROC1 knocked out. However, overexpressing ROC8 alone did not correct the leaf phenotype in ROC1 knockout plants, indicating a unique regulatory role for ROC1. The findings build on previous studies that have explored the genetic basis of leaf morphology and its impact on plant traits. For instance, the NAL7 gene mutation in rice, which affects leaf width through auxin biosynthesis, also demonstrated how genetic alterations can influence leaf structure without significant cellular changes, except in bulliform cells[4]. Similarly, the RL14 gene was shown to affect water transport and cell wall composition in rice leaves, linking genetic factors to changes in leaf morphology and drought response[2]. Overall, the study by the Chinese Academy of Sciences provides valuable insights into the genetic regulation of leaf rolling in rice. By understanding how ROC1 and its interactions with ROC5 and ROC8 influence bulliform cell size and leaf rolling, researchers can develop strategies to enhance drought resistance and optimize leaf morphology for improved crop yields. This research is crucial for addressing the challenges of water scarcity and increasing food production in the face of climate change[3].

AgricultureGeneticsPlant Science

References

Main Study

1) HD-ZIP IV Gene ROC1 Regulates Leaf Rolling and Drought Response Through Formation of Heterodimers with ROC5 and ROC8 in Rice

Published 27th July, 2024

https://doi.org/10.1186/s12284-024-00717-9

Related Studies

2) Rolling-leaf14 is a 2OG-Fe (II) oxygenase family protein that modulates rice leaf rolling by affecting secondary cell wall formation in leaves.

https://doi.org/10.1111/j.1467-7652.2012.00679.x

3) General mechanisms of drought response and their application in drought resistance improvement in plants.

https://doi.org/10.1007/s00018-014-1767-0

4) NARROW LEAF 7 controls leaf shape mediated by auxin in rice.

https://doi.org/10.1007/s00438-008-0328-3


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