BROTHER OF BRAINBOW DELETION MUTAGENESIS
Mutagenesis is a fundamental tool for studying gene function. One can use clonal deletion methods to eliminate the wild-type allele in a tissuespecific manner, thereby uncovering gene functions in different regions of the organism. Wachsman et al. (pages 2581–2591) report on the Brother of Brainbow system, which creates specific deletion clones of gametophytic essential genes. The cover displays confocal images of fluorescently marked Brother of Brainbow clones in Arabidopsis roots. The middle panel shows a root tip 3 days after long heat-shock induction of CRE, leading to formation of broad clones. The outer roots show the six possible expression combinations as a result of single (cyan fluorescent protein or red fluorescent protein together with yellow fluorescent protein), double (magenta, cyan fluorescent protein, or red fluorescent protein), or no (yellow fluorescent protein) recombination event(s) in the parental germ cells, mediated by CRE recombinase.
PLANT CELL:中国计量大学揭示病毒提高植物耐旱的机制
病毒会提高植物对干旱胁迫的耐受性。本研究发现 cowpea mild mottle virus (CPMMV)侵染会通过 small interfering RNA (vsiRNA)诱导的细胞自噬来提高common bean (Phaseolus vulgaris)对干旱胁迫的耐受性。
作者发现一个来自CPMMV Triple Gene Block1 (TGB1) 的21-bp vsiRNA 可以靶定宿主的Teosinte branched 1, Cycloidea, Proliferating Cell Factor (TCP) transcription factor gene PvTCP2的 5' untranslated region (UTR)从而抑制它的表达，这会诱导 autophagy-related gene (ATG) PvATG8c的表达, 从而激活细胞自噬效应。
下游的效应子EARLY RESPONSIVE TO DEHYDRATION (ERD) effector PvERD15 与拟南芥的AtERD15同源，它参与了气孔导度的调控，该基因被PvATG8c介导的细胞自噬降解，从而导致气孔导度下降。
小结：本研究揭示了TGB1-PvTCP2-PvATG8c-PvERD15 模块在植物-病毒互作过程中提高植物耐受干旱胁迫的机制。
A proposed model outlining the TGB1-vsiRNA6163-PvTCP2-PvATG8c-PvERD15 module associated with CPMMV-induced drought tolerance. In the absence of CPMMV infection, the transcription repressor PvTCP2 suppresses the expression of PvATG8c. Consequently, PvATG8c degrades PvERD15 at a low level, resulting in a high degree of stomatal opening. However, upon CPMMV infection, vsiRNA6163 is produced, leading to the cleavage of PvTCP2 at 5’-UTR and downregulation of PvTCP2. This downregulation activates the expression of PvATG8c. Subsequently, more PvERD15 is degraded, leading to reduced stomatal aperture and an enhanced drought tolerance phenotype.
原文：A viral small interfering RNA-host plant mRNA pathway modulates virus-induced drought tolerance by enhancing autophagy
