Spike development of wheat line 3558M was strongly inhibited by low temperature stress in spring. The fertile tiller inhibition (ftin) gene in the wheat line 3558M is associated with multiple phenotypes, including the production of fewer tillers, delayed floral transition, and death of the shoot apical meristem. In order to study the relationship between spike development inhibition and response to cold stress, we systematically investigated the genes and pathways underlying the differences using ITRAQ proteomics and RNA-sequencing technologies. The results showed that the cold acclimation pathway and multiple defence responses, including reactive oxygen species-mediated hypersensitive response, salicylic acid-mediated systemic acquired resistance, are activated and led to apex death of the wheat line 3558M under cold stress. Meanwhile, the cold acclimation pathway inhibited the SVP-SCO1-LFY flowering pathway and led to delayed floral transition. Two TaPIN proteins were significantly downregulated, and multiple auxin signalling genes were also differentially expressed. Particularly, knocking down the two TaPIN genes using RNAi technology significantly reduced the tiller number. The cold stress might disrupt the distribution of auxin and reduce the tillers of 3558M. Taken together, the ftin gene might be a cold-sensitive mutation and that is the cause of multiple biological pathways and phenotypic changes.

Spike development of wheat is closely associated with the ability of response to cold stress and inhibited under cold stress in spring. Morphological investigation showed that the ftin gene in 3558M is associated with multiple phenotypic characteristics, including fewer tillers, delayed floral transition, and the death of shoot apical meristem. In this study, we systematically researched the genetic nature of spike development using ITRAQ, transcriptome sequencing, western blot and RNAi technologies. The results showed that the ftin mutant is cold sensitive and activates the cold acclimation pathway. Multiple defence responses, including the ROS-mediated hypersensitive response, SA-mediated systemic acquired resistance and FLS2-induced pathogen-associated defence response, were activated to respond to normal cold stress and led to the apex death. Meanwhile, the continuous cold acclimation pathway inhibited the SVP-SCO1-LFY flowering pathway and leads to inhibition of spike development. Two TaPIN proteins were significantly downregulated, and multiple auxin signalling genes were also differentially expressed after cold stress. We used RNAi technology to knock down the two TaPIN genes and the tiller number was significantly reduced in TaPINa-RNAi and TaPINb-RNAi wheat. Taken together, the results revealed that the ftin gene might directly or indirectly regulate multiple biological pathways to affect multiple phenotypic characteristics.

Spike development of wheat is closely associated with the ability of response to cold stress and inhibited under cold stress in spring. Morphological investigation showed that the ftin gene in 3558M is associated with multiple phenotypic characteristics, including fewer tillers, delayed floral transition, and the death of shoot apical meristem. In this study, we systematically researched the genetic nature of spike development using ITRAQ, transcriptome sequencing, western blot and RNAi technologies. The results showed that the ftin mutant is cold sensitive and activates the cold acclimation pathway. Multiple defence responses, including the ROS-mediated hypersensitive response, SA-mediated systemic acquired resistance and FLS2-induced pathogen-associated defence response, were activated to respond to normal cold stress and led to the apex death. Meanwhile, the continuous cold acclimation pathway inhibited the SVP-SCO1-LFY flowering pathway and leads to inhibition of spike development. Two TaPIN proteins were significantly downregulated, and multiple auxin signalling genes were also differentially expressed after cold stress. We used RNAi technology to knock down the two TaPIN genes and the tiller number was significantly reduced in TaPINa-RNAi and TaPINb-RNAi wheat. Taken together, the results revealed that the ftin gene might directly or indirectly regulate multiple biological pathways to affect multiple phenotypic characteristics.