Crosstalk with Jasmonic Acid Integrates Multiple Responses in Plant Development

Abstract

To date, extensive studies have identified many classes of hormones in plants and revealed the specific, nonredundant signaling pathways for each hormone. However, plant hormone functions largely overlap in many aspects of plant development and environmental responses, suggesting that studying the crosstalk among plant hormones is key to understanding hormonal responses in plants. The phytohormone jasmonic acid (JA) is deeply involved in the regulation of plant responses to biotic and abiotic stresses. In addition, a growing number of studies suggest that JA plays an essential role in the modulation of plant growth and development under stress conditions, and crosstalk between JA and other phytohormones involved in growth and development, such as gibberellic acid (GA), cytokinin, and auxin modulate various developmental processes. This review summarizes recent findings of JA crosstalk in the modulation of plant growth and development, focusing on JA-GA, JA-cytokinin, and JA-auxin crosstalk. The molecular mechanisms underlying this crosstalk are also discussed.

Keywords: auxin; crosstalk; cytokinin; gibberellic acid; jasmonic acid.

Figure 1

A schematic of crosstalk between jasmonic acid (JA) and gibberellic acid (GA) in coordination between plant growth and defense. JA and GA antagonistically interact to coordinate plant growth and defense, and the crosstalk is mediated by direct interaction between JA signaling repressors, JASMONATE ZIM-DOMAIN (JAZs), and GA signaling repressors, DELLAs. MYCs and PHYTOCHROME INTERACTING FACTORS (PIFs) indicates transcription factors responsible for transcription of JA-responsive and GA-responsive genes, respectively. The arrows and T bars indicate positive and negative regulation, respectively.

Figure 2

A schematic of crosstalk between JA and cytokinin in xylem development. JA antagonistically interacts with cytokinin in xylem development and the JA-responsive MYC2 transcription factor mediates this process. MYC2 negatively regulates cytokinin response by promoting expression of AHP6, a cytokinin signaling inhibitor. The arrows and T bars indicate positive and negative regulation, respectively.

Figure 3

A schematic of crosstalk between JA and auxin in root development. PLT1 and 2 transcription factors are key regulators of root development downstream auxin. JA inhibits root growth, and MYC2 transcription factor mediates this development process by reducing expression of PLT1 and 2. The arrows and T bars indicate positive and negative regulation, respectively.