How Plant Hormones Work Together to Shape Tomato Growth

Jenn Hoskins
26th May, 2024

How Plant Hormones Work Together to Shape Tomato Growth

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at China Agricultural University discovered that the protein SlPP2C2 integrates ABA and auxin signals to regulate tomato development
  • SlPP2C2 interacts with enzymes and proteins involved in auxin biosynthesis and signaling, affecting gene expression and hormone levels
  • Manipulating SlPP2C2 expression led to significant changes in tomato plant morphology, indicating its crucial role in hormone balance and development
Abscisic acid (ABA) and auxin are two crucial plant hormones that regulate various aspects of plant growth and development. While their individual roles have been extensively studied, the interaction between ABA and auxin signaling pathways during tomato development has remained largely unexplored. A recent study conducted by researchers at China Agricultural University sheds light on this interaction, revealing how type 2C protein phosphatase (SlPP2C2) plays a pivotal role in integrating ABA and auxin signals to regulate tomato development[1]. The study found that SlPP2C2 interacts with flavin monooxygenase FZY, an enzyme involved in the biosynthesis of indole-3-acetic acid (IAA, a form of auxin), and small auxin upregulated RNA (SAUR), a protein involved in IAA signaling. This interaction affects the activity of these molecules and subsequently influences the expression of IAA-responsive genes. The expression level of SlPP2C2 was observed to increase in response to exogenous ABA, IAA, salt (NaCl), or dehydration treatments in various tomato tissues, including fruits, leaves, and seeds. Conversely, SlPP2C2 levels decreased in imbibed seeds. To further understand the role of SlPP2C2, the researchers manipulated its expression using overexpression, RNA interference, and CRISPR/Cas9-mediated genome editing techniques. These manipulations resulted in a range of morphological changes in tomato plants, such as alterations in leaf shape, stem trichomes, floral organs, and fruit development. These changes were accompanied by variations in IAA and ABA levels, indicating that SlPP2C2 plays a significant role in regulating hormone balance and plant morphology. The study also employed RNA sequencing (RNA-seq) analysis to examine the expression of auxin-/IAA-responsive genes in different tomato tissues. The results showed that SlPP2C2 regulates the expression of these genes, demonstrating its role in the cross-talk between ABA and auxin signaling pathways. This cross-talk is crucial for the development of both vegetative and reproductive organs in tomatoes. Previous studies have highlighted the importance of PP2Cs in ABA signaling. For instance, clade A protein phosphatases type 2C (PP2Cs) are known to be negative regulators of ABA signaling[2]. These PP2Cs are inhibited by PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS (RCAR) intracellular receptors in an ABA-dependent manner. The differential sensitivity of PP2Cs to inhibition by ABA receptors reveals a functional specialization of PYR/PYL ABA receptors to preferentially inhibit certain PP2Cs[2]. Additionally, HAI PP2Cs have been shown to interact with specific PYL receptors, contributing to drought resistance traits and ABA-independent phenotypes[3]. The current study expands on these findings by demonstrating that SlPP2C2 not only interacts with ABA signaling components but also integrates auxin signaling through its interaction with FZY and SAUR. This integration is crucial for the regulation of tomato development, affecting various physiological processes and gene expressions. Moreover, the study ties into previous research on auxin's role in fruit development. For example, altered auxin sensitivity has been shown to modify metabolism and fruit growth in tomatoes[4]. The current findings provide a more comprehensive understanding of how ABA and auxin signaling pathways intersect to regulate these developmental processes. In summary, the study conducted by China Agricultural University reveals that SlPP2C2-mediated ABA signaling regulates tomato development by interacting with key components of the auxin signaling pathway. This interaction integrates ABA and auxin signals, affecting the expression of development-related genes and leading to significant morphological and physiological changes in tomato plants. These findings not only advance our understanding of hormone signaling cross-talk but also have potential implications for improving crop yield and stress resistance in agricultural practices.

GeneticsBiochemPlant Science

References

Main Study

1) SlPP2C2 interacts with FZY/SAUR and regulates tomato development via signaling crosstalk of ABA and auxin.

Published 25th May, 2024

https://doi.org/10.1111/tpj.16818

Related Studies

2) Selective inhibition of clade A phosphatases type 2C by PYR/PYL/RCAR abscisic acid receptors.

https://doi.org/10.1104/pp.111.188623

3) Unique drought resistance functions of the highly ABA-induced clade A protein phosphatase 2Cs.

https://doi.org/10.1104/pp.112.202408

4) Reduced auxin signalling through the cyclophilin gene DIAGEOTROPICA impacts tomato fruit development and metabolism during ripening.

https://doi.org/10.1093/jxb/erac143


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