Abstract
BackgroundSenescence affects the quality and yield of plants by regulating different traits of plants. A few members of S40 gene family, the barley HvS40 and the Arabidopsis AtS40–3, have been shown to play a role in leaf senescence in Barley and Arabidopsis. Although we previously reported that S40 family exist in most of plants, up to now, no more function of S40 members in plant has been demonstrated. The aim of this study was to provide the senescence related information of S40 gene family in rice as rice is a major crop that feeds about half of the human population in the world.ResultsA total of 16 OsS40 genes were identified from the genome database of Oryza sativa L. japonica by bioinformatics analysis. Phylogenetic analysis reveals that the 16 OsS40 proteins are classified into five groups, and 4 of the 16 members belong to group I to which also the HvS40 and AtS40–3 is assigned. S40 genes of rice show high structural similarities, as 13 out of the 16 genes have no intron and the other 3 genes have only 1 or 2 introns. The expression patterns of OsS40 genes were analyzed during natural as well as stress-induced leaf senescence in correspondence with senescence marker genes. We found that 6 of them displayed differential but clearly up-regulated transcript profiles under diverse situations of senescence, including darkness, nitrogen deficiency, hormone treatments as well as pathogen infection. Furthermore, three OsS40 proteins were identified as nuclear located proteins by transient protoplast transformation assay.ConclusionsTaking all findings together, we concluded that OsS40–1, OsS40–2, OsS40–12 and OsS40–14 genes have potential regulatory function of crosstalk among abiotic, biotic and developmental senescence in rice. Our results provide valuable baseline for functional validation studies of the rice S40 genes in rice leaf senescence.
Highlights
Senescence affects the quality and yield of plants by regulating different traits of plants
Identification and characterization of the rice S40 genes S40 belongs to DUF584 Family, it contains DUF584 domain, the sequence: GRXLKGR(D/E)(L/M)XXXR(D/ N/T)X(I/V)XXXXG(F/I) is shared by all members belong to DUF584 group
The barley HvS40 gene encodes a member of the DUF584 group gene while in Arabidopsis, fifteen proteins belong to this family that was classified into five groups based on similarities of their amino acid sequences [22]
Summary
Senescence affects the quality and yield of plants by regulating different traits of plants. Leaf senescence is an integral part of the final stages of plant development, and is controlled by a fine-tuned complex regulatory network [1] Internal factors such as age of plants, hormones and external (a) biotic factors affects the regulation of leaf senescence [2]. Most of the SAGs are expressed during age dependent senescence, but are expressed during stress induced senescence, such as wounding, darkness, desiccation, treatments of the leaves with hormones and in response to pathogen infections [2, 13] These SAGs are activated by different transcription factors (TFs), among which NAC and WRKY are the two major groups that are involved in plant senescence [3]. The expression of numerous SAGs can be influenced by the regulation of a specific gene that encodes a specific TF [14]
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