SDG26 Is Involved in Trichome Control in Arabidopsis thaliana: Affecting Phytohormones and Adjusting Accumulation of H3K27me3 on Genes Related to Trichome Growth and Development

Abstract

Plant trichomes formed by specialized epidermal cells play a role in protecting plants from biotic and abiotic stresses and can also influence the economic and ornamental value of plant products. Therefore, further studies on the molecular mechanisms of plant trichome growth and development are important for understanding trichome formation and agricultural production. SET Domain Group 26 (SDG26) is a histone lysine methyltransferase. Currently, the molecular mechanism by which SDG26 regulates the growth and development of Arabidopsis leaf trichomes is still unclear. We found that the mutant of Arabidopsis (sdg26) possessed more trichomes on its rosette leaves compared to the wild type (Col-0), and the trichome density per unit area of sdg26 is significantly higher than that of Col-0. The content of cytokinins and jasmonic acid was higher in sdg26 than in Col-0, while the content of salicylic acid was lower in sdg26 than in Col-0, which is conducive to trichome growth. By measuring the expression levels of trichome-related genes, we found that the expression of genes that positively regulate trichome growth and development were up-regulated, while the negatively regulated genes were down-regulated in sdg26. Through chromatin immunoprecipitation sequencing (ChIP-seq) analysis, we found that SDG26 can directly regulate the expression of genes related to trichome growth and development such as ZFP1, ZFP5, ZFP6, GL3, MYB23, MYC1, TT8, GL1, GIS2, IPT1, IPT3, and IPT5 by increasing the accumulation of H3K27me3 on these genes, which further affects the growth and development of trichomes. This study reveals the mechanism by which SDG26 affects the growth and development of trichomes through histone methylation. The current study provides a theoretical basis for studying the molecular mechanism of histone methylation in regulating leaf trichome growth and development and perhaps guiding the development of new crop varieties.

Mapping and Detection of Genes Related to Trichome Development in Black Gram (Vigna mungo (L.) Hepper)

“…Trichomes are the first line of defense for plants in that they protect stems and leaves against pathogen or herbivore attack [ 1 , 2 , 3 ]. They also play important roles in the induction of pollination, resistance in extreme environments, protection against ultraviolet radiation and high temperatures, prevention of mechanical damage, and tolerance to heavy metals, drought, and salinity [ 4 ]. Trichomes are large, specialized epidermal cells that are distributed on various organs of a plant’s above-ground parts.…”

“…Trichomes are large, specialized epidermal cells that are distributed on various organs of a plant’s above-ground parts. They are involved in development and help to prevent excess transpiration [ 4 , 5 ]. There are two types of trichomes: non-glandular epidermal trichomes (bristles and hairs) and glandular trichomes.…”

“…Then, the bHLH transcription factors GLABRA3 (GL3) and ENHANCER OF GL3 (EGL3) interact with the WD-40 repeat-containing protein TRANSPARENT TESTA GLABRA1 (TTG1) to form the MBW (MYB-bHLH-WD40) complex, which activates the expression of the homeodomain–leucine zipper (HD ZIP) protein GLABRA2 (GL2) to promote trichome formation. The negative regulators Caprice (CPC) , Tripty Chon (TRY) , Enhancer of TRY and CPC1 (ETC1) , and Enhancer of TRY and CPC2 (ETC2) function redundantly to negatively regulate the development of trichome through the repression of GL3 , EGL3 , and TTG1 [ 4 , 8 ]. The hormones gibberellin, cytokinin, jasmonic acid, and brassinolide promote the occurrence of trichomes, while salicylic acid (SA) inhibits the growth and development of trichomes by interfering with the jasmonate pathway [ 4 ].…”

“…The negative regulators Caprice (CPC) , Tripty Chon (TRY) , Enhancer of TRY and CPC1 (ETC1) , and Enhancer of TRY and CPC2 (ETC2) function redundantly to negatively regulate the development of trichome through the repression of GL3 , EGL3 , and TTG1 [ 4 , 8 ]. The hormones gibberellin, cytokinin, jasmonic acid, and brassinolide promote the occurrence of trichomes, while salicylic acid (SA) inhibits the growth and development of trichomes by interfering with the jasmonate pathway [ 4 ]. Genes involved in the formation and development of glandular trichomes have been studied in detail in Solanum species, too.…”

Development and Biomechanics of Grewia lasiocarpa E. Mey. Ex Harv. Trichomes Exudate

“…Salicylic acid (SA), gibberellins (GA), Cytokinin (CTK), and Jasmonic acid (JA), are examples of phytohormones that have been demonstrated to influence trichome initiation and morphogenesis [20,33]. Additionally, research has demonstrated that the expression of several genes, including GLABRA1 (GL1) and TRANSPARENT TESTA GLABRA1 (TTG1), is essential for the growth of trichomes [34,35]. Understanding the complex interactions between these variables can help explain how trichome formation is regulated and how it might be used in biotechnology and agriculture.…”