Identification of the Regulators of Epidermis Development under Drought- and Salt-Stressed Conditions by Single-Cell RNA-Seq

Abstract

As sessile organisms, plants constantly face challenges from the external environment. In order to meet these challenges and survive, plants have evolved a set of sophisticated adaptation strategies, including changes in leaf morphology and epidermal cell development. These developmental patterns are regulated by both light and hormonal signaling pathways. However, our mechanistic understanding of the role of these signaling pathways in regulating plant response to environmental stress is still very limited. By applying single-cell RNA-Seq, we determined the expression pattern of PHYTOCHROME INTERACTING FACTOR (PIF) 1, PIF3, PIF4, and PIF5 genes in leaf epidermal pavement cells (PCs) and guard cells (GCs). PCs and GCs are very sensitive to environmental stress, and our previous research suggests that these PIFs may be involved in regulating the development of PCs, GCs, and leaf morphology under environmental stress. Growth analysis showed that pif1/3/4/5 quadruple mutant maintained tolerance to drought and salt stress, and the length to width ratio of leaves and petiole length under normal growth conditions were similar to those of wild-type (WT) plants under drought and salt treatment. Analysis of the developmental patterns of PCs and GCs, and whole leaf morphology, further confirmed that these PIFs may be involved in mediating the development of epidermal cells under drought and salt stress, likely by regulating the expression of MUTE and TOO MANY MOUTHS (TMM) genes. These results provide new insights into the molecular mechanism of plant adaptation to adverse growth environments.

PIN1 regulates epidermal cells development under drought and salt stress using single-cell analysis

“…These unfavorable factors invoke changes in plant growth patterns, regulating cell form and function, which plays a role in plant growth style. Although we previously analyzed the role of PHYTOCHROME INTERACTING FACTOR (PIF) 1, PIF3, PIF4, and PIF5 in PCs and GCs development under drought and salt stress (Liu et al, 2022b), no mechanism has yet been proposed for the role of PIN1 in PCs and GCs development under drought and salt stress conditions. Here, we investigated the role of PIN1 in drought and salt stress regulation of the developmental patterns of PCs and GCs in Arabidopsis leaves.…”

“…Histochemical GUS staining was performed as previously described (Liu et al, 2022b). Samples were fixed in 90% acetone at -20°C, rinsed four times with 0.1M sodium phosphate buffer (pH 7.4), and then incubated in X-Gluc solution [0.1M sodium phosphate (pH 7.4), 3 mM potassium ferricyanide, 0.5 mM potassium ferrocyanide, 0.5 g l -1 5-bromo-4-chloro-3-indolyl-bd-glucuronide cyclohexilammonium salt] at 37°C.…”

“…Signals from environmental stress induce the expression of temporary regulatory networks, which promotes an overall defense process in plants. A large number of studies have uncovered major genes that regulate leaf epidermal cells development in plants subjected to drought and salt stress (Fricke et al, 2006;Maricle et al, 2009;Taleisnik et al, 2009;Garrido et al, 2014;Zhang et al, 2018;Liu et al, 2022b). This study investigated the role of PIN1 in the development of plant epidermal cells under drought and salt stress.…”

“…As a result of global warming and possible climate anomalies, plants often encounter a high level of biotic and abiotic stresses, which engage them in challenging moments that affect their survival and yield (Ramegowda and Senthil-Kumar, 2015;Wang et al, 2021b). During such conditions, plants tend to fine-tune their developmental process and environmental response via changes in several transcriptional and metabolic programs (Sun et al, 2007;Sun et al, 2010;Meng et al, 2016;Bawa et al, 2019;Guo et al, 2019;Tang et al, 2019;Sun et al, 2020;Li et al, 2021;Zhou et al, 2021;Liu et al, 2022b;Mostofa et al, 2022;Wu et al, 2022a;Yeshi et al, 2022). For example, drought and salt stress regulate plant growth and development (Li et al, 2016;Devkar et al, 2020;Zelm et al, 2020;Zhang et al, 2020;Karimi et al, 2021;Zhang et al, 2022), and a large number of plants respond to drought stress via reducing water loss through stomatal closure (Daszkowska-Golec and Szarejko, 2013;Pirasteh-Anosheh et al, 2016) as well as decreasing rate of leaf expansion under salt stress condition (Rasool et al, 2013;Muchate et al, 2016;Ullah et al, 2020).…”

“…Leaf epidermis plays several key functions including regulating the exchange of gases, water, and nutrients with the surroundings (Zuch et al, 2021). However, the development and function of leaf epidermal cells, such as pavement cells (PCs) and guard cells (GCs), are sometimes disrupted by external environmental factors (Kebbas et al, 2015;Dong et al, 2018;Liu et al, 2022b).…”