Cover image: Pictured are Australian finger lime fruits collected from the Givaudan Citrus Variety Collection at the University of California, Riverside. Chien-Yu Huang et al. identified a stable antimicrobial peptide from Huanglongbing-tolerant Australian finger limes (Microcitrus australasica) that was capable of inhibiting Candidatus Liberibacter asiaticus, the bacterium that causes the disease Huanglongbing in citrus trees. This peptide inhibited infection when applied on citrus trees and may provide an effective and practical means of controlling Huanglongbing, which currently costs the global citrus industry billions of dollars annually. See the article by Huang et al., e2019628118. Image credit: Chien-Yu Huang.
新植物学家：新加坡科学家揭示影响植物早衰的新机制
The mediator complex是真核生物中高度保守的蛋白复合物，参与了植物基因的转录调控，它通过与转录因子互作来影响靶基因的表达。转录因子ORESARA1 (ORE1)参与了氮亏缺条件下的叶片衰老过程。本研究显示来自拟南芥的MED19a可以与ORE1发生互作来激活下游基因的表达。
在氮饥饿条件下MED19a形成一种nuclear condensates，这与其赖氨酸酰基化修饰下降有关。MED19a 的carboxyl terminus (cMED19a)含有一个mixed-charged intrinsically disordered region (MC-IDR)是其与ORE1互作所必需的。人类的 cMED19 可以部分回补med19a突变体表型，说明该基因的功能高度保守。
小结：本研究揭示了MED19参与调控叶片衰老的分子机制。
原文：Nutrient status regulates MED19a phase separation forORESARA1-dependent senescence
