Abstract
NAC proteins comprise of a plant-specific transcription factor (TF) family and play important roles in plant development and stress responses. Switchgrass (Panicum virgatum) is the prime candidate and model bioenergy grass across the world. Excavating agronomically valuable genes is important for switchgrass molecular breeding. In this study, a total of 251 switchgrass NAC (PvNACs) family genes clustered into 19 subgroups were analyzed, and those potentially involved in stress response or tissue-specific expression patterns were pinpointed. Specifically, 27 PvNACs were considered as abiotic stress-related including four membrane-associated ones. Among 40 tissue-specific PvNACs expression patterns eight factors were identified that might be relevant for lignin biosynthesis and/or secondary cell wall formation. Conserved functional domains and motifs were also identified among the PvNACs and potential association between these motifs and their predicted functions were proposed, that might encourage experimental studies to use PvNACs as possible targets to improve biomass production and abiotic stress tolerance.
Highlights
NAC transcription factors (TFs) are the largest and plant-specific TF family[1, 2], with the featured NAC domain firstly found in the N-terminal of petunia NAM, Arabidopsis thaliana ATAF1/2 and CUC2 and named after those three genes[3,4,5]
“Panicum virgatum v1.1, DOE-JGI” and the Hidden Markov Model (HMM) file PF02365 for the NAC domain were used for the identification of PvNACs in this study
A total of 251 switchgrass NAC proteins were identified and designated as PvNAC1 to PvNAC251 (Additional file 1) according to their orders in the chromosomes (The PvNACs started naming from chromosome 1a to 09b), and the rest PvNACs not designated onto its chromosomes were named according to the order of their IDs from the smallest to the largest
Summary
NAC transcription factors (TFs) are the largest and plant-specific TF family[1, 2], with the featured NAC domain firstly found in the N-terminal of petunia NAM, Arabidopsis thaliana ATAF1/2 and CUC2 and named after those three genes[3,4,5]. The TARs appear to have conserved motifs corresponding to their NAC domain structures, suggesting that NAC proteins in each subgroup might evolve to have similar functions[8] This working model proposed by Ooka[8] has been proven to be valid in many studies using experimental approaches, and could be used as a basis for target gene identification and characterization in switchgrass as well. Seven membrane-bound ZmNTL genes were identified in maize (Zea mays) that were up-regulated upon hydrogen peroxide or abscisic acid treatment suggesting their involvement in abiotic stress tolerance[19] These previous results from model plants together with featured functional domains (or subdomains) among the NAC family genes provide valuable insights into translational research on target gene identification and functional prediction in bioenergy as well as other agronomic crops. This study would provide an insight of a large number of candidate NAC genes for future genetic studies on switchgrass
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
