Genome-wide identification and expression analyses of the LEA protein gene family in tea plant reveal their involvement in seed development and abiotic stress responses

Abstract

Late embryogenesis abundant (LEA) proteins are widely known to be present in higher plants and are believed to play important functional roles in embryonic development and abiotic stress responses. However, there is a current lack of systematic analyses on the LEA protein gene family in tea plant. In this study, a total of 48 LEA genes were identified using Hidden Markov Model profiles in C. sinensis, and were classified into seven distinct groups based on their conserved domains and phylogenetic relationships. Genes in the CsLEA_2 group were found to be the most abundant. Gene expression analyses revealed that all the identified CsLEA genes were expressed in at least one tissue, and most had higher expression levels in the root or seed relative to other tested tissues. Nearly all the CsLEA genes were found to be involved in seed development, and thirty-nine might play an important role in tea seed maturation concurrent with dehydration. However, only sixteen CsLEA genes were involved in seed desiccation, and furthermore, most were suppressed. Additionally, forty-six CsLEA genes could be induced by at least one of the tested stress treatments, and they were especially sensitive to high temperature stress. Furthermore, it was found that eleven CsLEA genes were involved in tea plant in response to all tested abiotic stresses. Overall, this study provides new insights into the formation of CsLEA gene family members and improves our understanding on the potential roles of these genes in normal development processes and abiotic stress responses in tea plant, particularly during seed development and desiccation. These results are beneficial for future functional studies of CsLEA genes that will help preserve the recalcitrant tea seeds for a long time and genetically improve tea plant.

Peptide-Bound Methionine Sulfoxide (MetO) Levels and MsrB2 Abundance Are Differentially Regulated during the Desiccation Phase in Contrasted Acer Seeds

“…Based on their desiccation tolerance, seeds are classified as either orthodox (resistant) or recalcitrant (sensitive) [3]. Orthodox seeds survive extreme dehydration without a loss in viability; however, the conservation and propagation of recalcitrant seeds is much more difficult [4][5][6]. Desiccation tolerance is an essential adaptation that enabled the colonization of terrestrial habitats by early land plants; however, this adaptation was lost in some plants growing in environments where recalcitrance supports rapid germination [7].…”

Desiccation Tolerance as The Basis of Long-Term Seed Viability

“…Indeed, in total, 21 of 51 Arabidopsis genes encoding LEA proteins are expressed only in seeds and are directly involved in the control of their formation [18]. This tendency is even more pronounced in Camellia sinensis: 39 among 48 LEA genes detected in this plant might play an important role in seed maturation [26].…”

“…The largest group of LEA-proteins is represented by the LEA-2 family [18,20,26]. The proteins representing this family are featured with higher content of hydrophobic amino acids and conservative three-dimensional structure.…”

Desiccation Tolerance as the Basis of Long-Term Seed Viability

“…Indeed, in total, 21 of 51 Arabidopsis LEA genes are expressed only in seeds and are mostly directly involved in the control of their formation [ 18 ]. This tendency is even more pronounced in Camellia sinensis : 39 among 48 LEA genes detected in this plant might play an important role in seed maturation [ 26 ].…”