Seasonal nitrogen remobilization and the role of auxin transport in poplar trees

Abstract

Seasonal nitrogen (N) cycling in Populus, involves bark storage proteins (BSPs) that accumulate in bark phloem parenchyma in the autumn and decline when shoot growth resumes in the spring. Little is known about the contribution of BSPs to growth or the signals regulating N remobilization from BSPs. Knockdown of BSP accumulation via RNAi and N sink manipulations were used to understand how BSP storage influences shoot growth. Reduced accumulation of BSPs delayed bud break and reduced shoot growth following dormancy. Further, 13N tracer studies also showed that BSP accumulation is an important factor in N partitioning from senescing leaves to bark. Thus, BSP accumulation has a role in N remobilization during N partitioning both from senescing leaves to bark and from bark to expanding shoots once growth commences following dormancy. The bark transcriptome during BSP catabolism and N remobilization was enriched in genes associated with auxin transport and signaling, and manipulation of the source of auxin or auxin transport revealed a role for auxin in regulating BSP catabolism and N remobilization. Therefore, N remobilization appears to be regulated by auxin produced in expanding buds and shoots that is transported to bark where it regulates protease gene expression and BSP catabolism.

Transcriptomic Profiling of Populus Roots Challenged with Fusarium Reveals Differential Responsive Patterns of Invertase and Invertase Inhibitor-Like Families within Carbohydrate Metabolism

“…Some of them containing four indole-3-acetic acid-amido synthetase GH3.1 genes, an auxin-induced gene (Potri.001G177500), and an auxin-responsive gene (Potri.018G127800, IAA29.2 ) were significantly depressed. The latter one was in line with a more recent report that revealed a decreased expression of IAA29.2 during nitrogen remobilization [ 66 ]. Other enriched genes showing specific increases in the phytohormone signaling category contain two protein phosphatase 2C (PP2C) and three ET responsive transcription factors (ERFs).…”

Transcriptome analysis reveals multiple effects of nitrogen accumulation and metabolism in the roots, shoots, and leaves of potato (Solanum tuberosum L.)

“…It plays its regulatory role primarily by inducing the expression of early auxin response genes. The low nitrogen condition induced the biosynthesis of auxin and accumulation of transcripts, and the source of auxin or auxin transport revealed a role for auxin in regulating N remobilization [ 58 , 59 ]. Using WGCNA and co-expression methodology, we identified many DEGs involved in auxin -induced and auxin-regulated (Figs.…”

Transcriptome Analysis Reveals Multiple Effects of Nitrogen Accumulation and Metabolism in the Roots, Shoots, and Leaves of Potato (Solanum Tuberosum L.)

“…It plays its regulatory role primarily by inducing the expression of early auxin response genes. The source of auxin or auxin transport discovered a task for growth regulator in regulation N remobilization (Hu et al 2020;Li et al 2020). Using WGCNA and co-expression methodology, we tend to known many DEGs involved in Auxin-induced and Auxin-regulated (Figs.…”