1.
Jujube witches' broom phytoplasma effectors SJP1 and SJP2 induce lateral bud outgrowth by repressing the ZjBRC1-controlled auxin efflux channel.
Zhou, J, Ma, F, Yao, Y, Deng, M, Chen, M, Zhang, S, Li, Y, Yang, J, Zhang, N, Huang, J, et al
Plant, cell & environment. 2021;(10):3257-3272
Abstract
Comprehensively controlling phytoplasma-associated jujube witches' broom (JWB) disease is extremely challenging for the jujube industry. Although the pathogenesis of phytoplasma disease has been highlighted in many plant species, the release of lateral buds from dormancy under JWB phytoplasma infection has not been characterized in woody perennial jujube. Here, two 16SrV-B group phytoplasma effectors, SJP1 and SJP2, were experimentally determined to induce witches' broom with increased lateral branches. In vivo interaction and subcellular localization analyses showed that both SJP1 and SJP2 were translocated from the cytoplasm to the nucleus to target the CYC/TB1-TCP transcription factor ZjBRC1. The N- and C-terminal coiled-coil domains of SJP1 and SJP2 were required for the TCP-binding ability. ZjBRC1 bound directly to the auxin efflux carrier ZjPIN1c/3 promoters and down-regulated their expression to promote the accumulation of endogenous auxin indole-3-acetic acid in jujube calli. Furthermore, JWB phytoplasma infection suppressed ZjBRC1 accumulation and induced ZjPIN1c/3 expression to stimulate lateral bud outgrowth. Therefore, SJP1 and SJP2 stimulate lateral bud outgrowth, at least partly, by repressing the ZjBRC1-controlled auxin efflux channel in jujube, representing a potential strategy for comprehensive phytoplasma-associated disease control and a resource for gene editing breeding to create new cultivars with varying degrees of shoot branching.
2.
Phytochrome nuclear body: an emerging model to study interphase nuclear dynamics and signaling.
Chen, M
Current opinion in plant biology. 2008;(5):503-8
Abstract
In higher plants, one of the most striking effects of light at the cellular level is the formation of phytochrome nuclear bodies (PNBs). In Arabidopsis, two types of PNBs have been described: a transient type of PNBs (tPNBs), containing both phytochrome A and phytochrome B, observed during the dark-to-light transition and a relatively photo-stable type of phytochrome B-containing PNBs (sPNBs) under continuous light. Despite the separation of the cell-biological observations of PNBs from the traditional model of light signaling elucidated by genetic and biochemical approaches, a growing body of evidence indicates that PNBs are intimately involved in phytochrome signaling. Both positive and negative light signaling components have been colocalized to PNBs, which provides direct evidence bridging PNBs and phytochrome signaling. In particular, the sPNB serves as an excellent tractable marker for early phytochrome signaling events, and thus provides a remarkable genetic system to investigate the mechanistic connection between interphase subnuclear dynamics and cell signaling.