The miR164-TaNAC14 module regulates root development and abiotic-stress tolerance in wheat seedlings

Previous studies have revealed the miR164 family and the miR164-targeted NAC transcription factor genes in rice(Oryza sativa)and Arabidopsis that play versatile roles in developmental processes and stress responses.In wheat(Triticum aestivum L.),we found nine genetic loci of tae-miR164(tae-MIR164 a to i)producing two mature sequences that downregulate the expression of three newly identified target genes of TaNACs(TaNAC1,TaNAC11,and TaNAC14)by the cleavage of the respective mRNAs.Overexpression of tae-miR164 or one of its target genes(TaNAC14)demonstrated that the miR164-TaNAC14 module greatly affects root growth and development and stress(drought and salinity)tolerance in wheat seedlings,and TaNAC14 promotes root growth and development in wheat seedlings and enhances drought tolerance,while tae-miR164 inhibits root development and reduces drought and salinity tolerance by downregulating the expression of TaNAC14.These findings identify the miR164-TaNAC14 module as well as other taemiR164-regulated genes which can serve as new genetic resources for stress-resistance wheat breeding.

Selection and Validation of Reference Genes for Normalization of RT-qPCR Analysis in Developing or Abiotic-Stressed Tissues of Loquat (Eriobotrya japonica)

Loquat(Eriobotrya japonica Lindl.)is a subtropical evergreen fruit tree that produces fruits with abundant nutrients and medicinal components.Confirming suitable reference genes for a set of loquat samples before qRT-PCR experiments is essential for the accurate quantification of gene expression.In this study,eight candidate reference genes were selected from our previously published RNA-seq data,and primers for each candidate reference gene were designed and evaluated.The Cq values of the candidate reference genes were calculated by RT-qPCR in 31 different loquat samples,including 12 subgroups of developing or abiotic-stressed tissues.Different combinations of stable reference genes were screened according to a comprehensive rank,which was synthesized from the results of four algorithms,including the geNorm,NormFinder,BestKeeper andΔCt methods.The screened reference genes were verified by normalizing EjLGA1 in each subgroup.The obtained suitable combinations of reference genes for accurate normalization were GAPDH,EF1αand ACT for floral development;GAPDH,UBCE and ACT for fruit setting;EF1α,GAPDH and eIF2B for fruit ripening;ACT,EF1αand UBCE for leaves under heat stress;eIF2B,UBCE and EF1αfor leaves under freezing stress;EF1α,TUA and UBCE for leaves under salt stress;ACT,EF1αand eIF2B for immature pulp under freezing stress;ACT,UBCE and eIF2B for immature seeds under freezing stress;EF1α,eIF2B and UBCE for both immature pulp and seeds under freezing stress;UBCE,TUB and TUA for red-fleshed fruits under cold-storage stress;eIF2B,RPS3 and TUB for white-fleshed fruits under coldstorage stress;and eIF2B,UBCE and RPS3 for both red-and white-fleshed fruits under cold-storage stress.This study obtained different combinations of stable reference genes for accurate normalization in twelve subgroups of developing or abiotic-stressed tissues in loquat.To our knowledge,this is the first report to obtain stable reference genes for normalizing gene expression of abiotic-stressed tissues in E.japonica.The use of the three most stable reference genes could increase the reliability of future quantification experiments.