The PIN1 family gene PvPIN1 is involved in auxin-dependent root emergence and tillering in switchgrass

Abstract

Switchgrass (Panicum virgatum L.; family Poaceae) is a warm-season C4 perennial grass. Tillering plays an important role in determining the morphology of aboveground parts and the final biomass yield of switchgrass. Auxin distribution in plants can affect a variety of important growth and developmental processes, including the regulation of shoot and root branching, plant resistance and biological yield. Auxin transport and gradients in plants are mediated by influx and efflux carriers. PvPIN1, a switchgrass PIN1-like gene that is involved in regulating polar transport, is a putative auxin efflux carrier. Neighbor-joining analysis using sequences deposited in NCBI databases showed that the PvPIN1gene belongs to the PIN1 family and is evolutionarily closer to the Oryza sativa japonica group. Tiller emergence and development was significantly promoted in plants subjected toPvPIN1 RNA interference (RNAi), which yielded a phenotype similar to that of wild-type plants treated with the auxin transport inhibitor TIBA (2,3,5-triiodobenzoic acid). A transgenic approach that inducedPvPIN1 gene overexpression or suppression altered tiller number and the shoot/root ratio. These data suggest that PvPIN1plays an important role in auxin-dependent adventitious root emergence and tillering.

Salicylic Acid Enhances Adventitious Root and Aerenchyma Formation in Wheat under Waterlogged Conditions

“…Previous reports have also implicated SA in the regulation of the biosynthesis, transport and signaling of auxin, which acts as important regulator of tiller formation/branching in plants. For example, SA represses the expression of genes encoding auxin receptor (TIR1) and auxin importer and exporter (AUX1 and PIN7) [38], and such suppression of auxin transport and signaling has been shown to lead to an increase in the number of tillers [39,40]. Therefore, the prevalence of enhanced tiller formation in response to SA might suggest the suppression of auxin production/signaling and its transport.…”

Down-expression of TaPIN1s Increases the Tiller Number and Grain Yield in Wheat

“…Excessive tiller in cereal crop can lead to yield reductions because tillers compete for resources, and many secondary tillers are not fertile [31]. PIN1 genes play roles in the regulation of tiller number and tiller angle in rice [21] and switchgrass [17]. In this study, we found that the down-expression of TaPIN1s significantly increased tiller numbers at the tillering stage, jointing stage, and mature stage in wheat.…”

“…The initiation and growth of lateral branches (called tillers in grasses) are important factors in determining plant architecture and yield [12][13][14]. Previous studies have demonstrated that decreased auxin transport affects branching in the monocot plants, such as rice, maize, and switchgrass (Panicum virgatum) [15][16][17]. Auxin maxima created by PIN1 at the meristem surface are responsible for organ initiation [18,19].…”

Down-expression of TaPIN1s Increases the Tiller Number and Grain Yield in Wheat

“…Excessive tiller in cereal crop can lead to yield reductions because tillers compete for resources, and many secondary tillers are not fertile [ 31 ]. PIN1 genes play roles in the regulation of tiller number and tiller angle in rice [ 21 ] and switchgrass [ 17 ]. In this study, we found that the down-expression of TaPIN1s significantly increased tiller number at the tillering stage, jointing stage, and mature stage in wheat.…”

“…The initiation and growth of lateral branches (called tillers in grasses) are important factors in determining plant architecture and yield [ 12 – 14 ]. Previous studies have demonstrated that decreased auxin transport affects branching in the monocot plants, such as rice ( Oryza sativa ), maize ( Zea mays ), and switchgrass ( Panicum virgatum ) [ 15 – 17 ]. Auxin maxima created by PIN1 at the meristem surface are responsible for organ initiation [ 18 , 19 ].…”