Lipid transfer provides symbiotic fungi associated with plant roots with a source of carbon.

Root growth regulation by requirement: Plant productivity depends on the elemental nutrients nitrogen and phosphorus, which are drawn from the soil. Oldroyd and Leyser review how root growth patterns adjust according to the physiological needs of the above-ground plant. Systemic signals, including small peptide signals, mediate communication between the shoot's needs and the root's supply. Science , this issue p. eaba0196

Calcium signals the making of symbiosis: Plant cell nuclei respond to signals from symbiotic nitrogenfixing rhizobial bacteria or arbuscular mycorrhizal fungi with oscillating Ca ²⁺ release. Charpentier et al. identified a trio of responsible Ca ²⁺ channels in a legume. These channels contain nuclear localization signals and are expressed in root cell nuclear envelopes. The channels function early in the establishment of symbiosis to produce oscillations in Ca ²⁺ release from nuclear stores. Science , this issue p. 1102