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Most plant roots have multiple cortex layers that make up the bulk of the organ and play key roles in physiology, such as flood tolerance and symbiosis. However, little is known about the formation of cortical layers outside of the highly reduced anatomy of Arabidopsis . Here, we used single-cell RNA sequencing to rapidly generate a cell-resolution map of the maize root, revealing an alternative configuration of the tissue formative transcription factor SHORT-ROOT (SHR) adjacent to an expanded cortex. We show that maize SHR protein is hypermobile, moving at least eight cell layers into the cortex. Higher-order SHR mutants in both maize and Setaria have reduced numbers of cortical layers, showing that the SHR pathway controls expansion of cortical tissue to elaborate anatomical complexity. 

Biological hydrolysis of microcrystalline cellulose is an uncommon feature in the microbial world, especially among bacteria and archaea growing optimally above 70°C (the so‐called extreme thermophiles). In fact, among this group only certain species in the genusCaldicellulosiruptorare capable of rapid and extensive cellulose degradation. Four novel multidomain glycoside hydrolases (GHs) fromCaldicellulosiruptor morganiiandCaldicellulosiruptor danieliiwere produced recombinantly inCaldicellulosiruptor besciiand characterized. These GHs are structurally organized with two or three catalytic domains flanking carbohydrate binding modules from Family 3. Collectively, these enzymes represent GH families 5, 9, 10, 12, 44, 48, and 74, and hydrolyze crystalline cellulose, glucan, xylan, and mannan, the primary carbohydrates in plant biomass. Degradation of microcrystalline cellulose by cocktails of GHs from threeCaldicellulosiruptorspecies demonstrated that synergistic interactions enable mixtures of multiple enzymes to outperform single enzymes, suggesting a community mode of action for lignocellulose utilization in thermal environments. © 2018 American Institute of Chemical EngineersAIChE J, 64: 4218–4228, 2018