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Summary: The timing and extent of cell division are crucial for the correct patterning of multicellular organism. In Arabidopsis, root ground tissue maturation involves the periclinal cell division of the endodermis to generate two cell layers: endodermis and middle cortex. However, the molecular mechanism underlying this pattern formation remains unclear.Here, we report that phytohormone brassinosteroid (BR) and redox signal hydrogen peroxide (H2O2) interdependently promote periclinal division during root ground tissue maturation by regulating the activity of SHORT‐ROOT (SHR), a master regulator of root growth and development.BR‐activated transcription factor BRASSINAZOLE RESISTANT1 (BZR1) directly binds to the promoter of SHR to induce its expression, and physically interacts with SHR to increase the transcripts of RESPIRATORY BURST OXIDASE HOMOLOGs (RBOHs) and elevate the levels of H2O2, which feedback enhances the interaction between BZR1 and SHR. Additionally, genetic analysis shows that SHR is required for BZR1‐promoted periclinal division, and BZR1 enhances the promoting effects of SHR on periclinal division.Together, our finding reveals that the transcriptional module of BZR1‐SHR fine‐tunes periclinal division during root ground tissue maturation in response to hormone and redox signals. [ABSTRACT FROM AUTHOR]

Summary: Symbiotic nitrogen (N2) fixation plays a vital role in sustainable agriculture. Efficient N2 fixation requires various materials, including phosphate (Pi); however, the molecular mechanism underlying the transport of Pi into nodules and bacteroids remains largely unknown.A nodule‐localized Pi transporter, GmPT7, was functionally characterized in soybean (Glycine max) and its role in N2 fixation and yield was investigated via composite and whole transgenic plants.GmPT7 protein was localized to the plasma membrane and showed transport activity for Pi in yeast. Altered expression of GmPT7 changed 33Pi uptake from rhizosphere and translocation to bacteroids. GmPT7 was mainly localized to the outer cortex and fixation zones of the nodules. Overexpression of GmPT7 promoted nodulation, and increased plant biomass, shoot nitrogen and phosphorus content, resulting in improved soybean yield by up to 36%. Double suppression of GmPT5 and GmPT7 led to nearly complete elimination of nodulation and over 50% reduction in plant biomass, shoot nitrogen and phosphorus content, indicating that both GmPT7 and GmPT5 contribute to Pi transport for N2 fixation.Taken together, our results indicate that GmPT7 is a transporter responsible for direct Pi entry to nodules and further to fixation zones, which is required for enhancing symbiotic N2 fixation and grain yield of soybean. [ABSTRACT FROM AUTHOR]

Symbiotic nitrogen (N 2 ) fixation plays a vital role in sustainable agriculture. Efficient N 2 fixation requires various materials, including phosphate (Pi); however, the molecular mechanism underlying the transport of Pi into nodules and bacteroids remains largely unknown. A nodule-localized Pi transporter, GmPT7, was functionally characterized in soybean (Glycine max) and its role in N 2 fixation and yield was investigated via composite and whole transgenic plants. GmPT7 protein was localized to the plasma membrane and showed transport activity for Pi in yeast. Altered expression of GmPT7 changed 33 Pi uptake from rhizosphere and translocation to bacteroids. GmPT7 was mainly localized to the outer cortex and fixation zones of the nodules. Overexpression of GmPT7 promoted nodulation, and increased plant biomass, shoot nitrogen and phosphorus content, resulting in improved soybean yield by up to 36%. Double suppression of GmPT5 and GmPT7 led to nearly complete elimination of nodulation and over 50% reduction in plant biomass, shoot nitrogen and phosphorus content, indicating that both GmPT7 and GmPT5 contribute to Pi transport for N 2 fixation. Taken together, our results indicate that GmPT7 is a transporter responsible for direct Pi entry to nodules and further to fixation zones, which is required for enhancing symbiotic N 2 fixation and grain yield of soybean., (© 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.)