Identification and Expression Analysis of Zinc Finger A20/AN1 Stress-Associated Genes SmSAP Responding to Abiotic Stress in Eggplant

Abstract

Stress-associated proteins (SAP), a class of zinc-finger proteins, have been identified as novel stress regulatory proteins in stress responses. However, SAP genes in eggplant (SmSAP) have been little reported. It has important significance in identifying SAP members, understanding the molecular mechanisms underlying stress responses, and tolerance. We performed a comprehensive study of the A20/AN1 domains, motifs, gene structures, phylogenetic relationships, chromosomal locations, gene replications, collinearity, cis-acting elements, and expression pattern responses to various abiotic stresses. Twenty-one SAP genes were identified in eggplant (SmSAP) and were localized on 10 chromosomes. A phylogenetic analysis revealed that most of the SmSAP proteins showed a high homology with the tomato SAP members, and 21 members were divided into four groups based on the homology of the SAP members in eggplant, tomato, rice, and Arabidopsis. Further analysis revealed that SmSAP proteins contain the characteristic A20/AN1 domains, the A20 domain composed of motif 2 (ILCINNCGFFGSPATMNLCSKCYKDMJLK). Four pairs of tandem duplications were found in eggplant, and 10 SmSAP genes had collinearity with SAP genes from Arabidopsis, potato, or tomato, but only four SmSAP genes were collinear with SAP genes in the three species mentioned above. Moreover, the promoters of SmSAP genes were predicted to contain many cis-acting elements that respond to abiotic stress and hormones. A qRT-PCR analysis of the four selected SmSAP genes exhibited diverse expression levels in response to various environmental stresses. These results provided a comprehensive analysis of the SmSAP genes and lay a solid foundation for improving the understanding of the functional diversification of SAP genes under various environmental stresses in eggplant.

Identification, Phylogeny, Divergence, Structure, and Expression Analysis of A20/AN1 Zinc Finger Domain Containing Stress-Associated Proteins (SAPs) Genes in Jatropha curcas L.

“…In present study, 11 SAP genes were identified genome-wide in Jetropha and the phylogenetic divided the JcSAP genes into four groups ( Figure 1 ); Synteny analysis showed that Jatropha SAP genes had a high homology with the Arabidopsis SAP genes ( Figure 2 ). These results are highly in consistence with the previously reported results of [ 1 , 2 ], suggesting very little variation in SAP gene family members.…”

“…Stress-associated proteins (SAP) are novel stress regulatory zinc-finger proteins and are strongly associated with tolerance against various abiotic stresses [ 1 , 12 , 13 , 14 , 15 ]. SAP gene family has previously identified and comprehensively studied in many plant species including Oryza sativa [ 5 ], Arabidopsis thaliana [ 5 ], Hordeum vulgare [ 13 ], Glycine max [ 12 ], Gossypium hirsutum [ 16 ], Solanum lycopersicum [ 2 ], Cucumis sativus [ 17 ], Solanum melongena [ 1 ], and Prunus dulcis [ 18 ], etc. However, there is no systematic study of SAP genes in the most important biofuel-producing shrub, Jatropha.…”

“…These environmental stresses down- or upregulate a large pool of genes. To eliminate or reduce the harsh environmental effect, plants have evolved complex internal molecular mechanisms to modulate stress-responsive or regulatory genes [ 1 , 2 ]. Regulatory genes code for sensors that perceive stress signals, kinases that transmit the signals, and transcription factors that are down- or upregulated as a result of perceived stress.…”

“…Stress-associated proteins (SAP) are the newly identified stress regulatory zinc-finger proteins in plants with the A20 domain at N-terminal and AN1 domain at C-terminal, and are mainly associated with tolerance against various environmental abiotic stresses [ 1 , 12 , 13 , 14 , 15 ]. SAP genes in plants were first identified in Oryza sativa , and OsSAP1 was declared to be largely involved in abscisic acid, healing wounds, heavy metals, salt, drought, and cold [ 9 ].…”

“…Recently, the response of SAP genes has been identified in several plant species and has been studied against various environmental stresses. The evidence from the previous literature has shown the presence of the SAP gene family in many species, like 18 SAP gene members in rice [ 5 ], 14 in Arabidopsis [ 5 ], 17 in barley [ 13 ], 27 in soybean [ 12 ], 37 in cotton [ 16 ], 13 in tomato [ 2 ], 12 in cucumber [ 17 ], 21 in eggplant [ 1 ], and 9 in almond [ 18 ]. However, the identification of SAP genes in Jatropha genome is not systematically deliberated.…”