Search

NAC transcription factors play a significant role in regulating plant responses to biological processes and environmental stresses. Our previous study revealed 21 ThNAC proteins, and ThNAC13 is a nuclear protein that responds to saline stress in Tamarix hispida. To determine whether ThNAC13 regulates downstream genes, RNA sequencing (RNA-seq) and DNA affinity purification sequencing (DAP-seq) were used to identify the binding sites of ThNAC13 at the whole-genome level. In RNAi-silenced ThNAC13 transgenic Tamarix , a total of 4 downregulated differentially expressed genes (DEGs) and 114 peaks strongly associated with four different motifs were identified compared with those in empty vector transgenic Tamarix under salt stress. The c48149.graph_c0 gene contains the key domain of the phloem protein 2 (PP2) protein and is a candidate gene downstream of ThNAC13. Yeast one-hybrid (Y1H), chromatin immunoprecipitation (ChIP) and dual-luciferase reporter (LUC) assays were used to identify ThNAC13 as an upstream regulator of ThPP2. Transgenic Tamarix plants in which ThPP2 was transiently expressed or silenced via RNAi were used for functional gain and loss experiments. The ThPP2- overexpressing plants exhibited decreased hydrogen peroxide (H 2 O 2), superoxide (O 2 •−), and electrolyte leakage (EL) and malondialdehyde (MDA) levels and increased superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity. In contrast, transient RNAi-mediated silencing of ThPP2 in Tamarix had the opposite effect. ThNAC13 binds to the promoter region of the ThPP2 gene and reduces the reactive oxygen species (ROS) accumulation and enhances antioxidant enzyme activity, positively regulating salt stress tolerance in Tamarix. • 4 down-regulated DEGs and 4 different motifs were identified in RNAi-silenced ThNAC13 compare with empty vector transgenic Tamarix under salt stress. • The phloem protein 2 (PP2) protein as a downstream gene by ThNAC13 TFs. • Overexpression of ThPP2 Tamarix decreased the contents of H 2 O 2 , O 2 •−, EL and MDA; induced the activities of SOD, POD and CAT. • In contrast, transiently RNAi-silenced ThPP2 Tamarix showed the opposite result. • ThNAC13 binds to ThPP2 gene through reduces the ROS accumulation and enhances antioxidant enzyme activity to improve salt stress tolerance. [ABSTRACT FROM AUTHOR]

Short tandem repeat (STR) multiplexes with the amelogenin (AMEL) gene as a gender marker have been used as a routine tool of forensic DNA analysis. It has been reported that AMEL-based gender detection could misidentify a known male as a female due to the dropout of amelogenin Y (AMELY) allele. Other gender markers, such as Y-chromosomal short tandem repeat (Y-STR), may be a substitution of AMEL and help the sex determination. In current study, employing AmpF lSTR® Sinofiler and AmpF lSTR® Y-filer™ PCR Amplification kit, 18 AMELY-negative males were identified. Accordingly, the incidence of the AMELY dropout was 0.227 ‰ (18/79,304) in Chinese population. Sequencing of AMELY allele and analyzing of azoospermia factors region suggested that 3 out of 18 misidentifications were induced by mutations in the primer-binding region of the AMELY, while other 15 sex misidentifications were results of Y chromosome microdeletions with variant lengths. Moreover, variant combination patterns of AMELY dropout and Y-STRs deletions were also observed. Our data suggested that Y-STR locus dropout may indicate more problems, especially in the mixed sample's interpretation. Results of haplogroup prediction showed that seven AMELY dropouts combined with variant Y-STR deletions can be classified as the J2 subdivision, suggesting that some of these Y chromosomes might descend from a common ancestor. [ABSTRACT FROM AUTHOR]