Fungi are among the most devastating pathogens of plants, including crops of major economic importance, and many vegetable crops. Several methods of control are commonly used to limit their pathogeny, including genetic and chemical controls.

但是，两者经常被绕开，因为真菌种群迅速发展对各种杀菌剂的抗性。在生态规模上，使用杀菌剂似乎也是一场灾难，因此正在努力寻找针对植物致病真菌的其他武器。

The29^th真菌遗传会议took place at the Asilomar Conference Grounds in California, USA, and was an important occasion to give an overview of a new weapon in the antifungal arsenal: small interfering RNAs (siRNAs) and small RNAs (sRNAs).

什么是sirnas和srnas？

siRNA是参与RNA干扰（RNAi）过程的短（21-24个碱基对）的非编码RNA，导致其特异性信使RNA（mRNA）靶标降解，从而抑制基因表达或翻译。

RNAi occurs in two steps: first the cellular double-stranded RNA are degraded by the Dicer ribonuclease to form 21-24 base pair long RNA fragments. Those small RNAs are then transferred to the RNA-induced silencing complex (RISC), a multiproteic complex that cleaves the double-stranded RNAs into a single strand form. In the second step of the RNAi, those single-stranded RNAs target the RISC complex to the complementary RNAs, leading to their degradation by the RISC complex.

In recent years, more and more efforts have been made to adapt siRNA for use in crop protection.

The existence of siRNAs in plant-fungal interactions has been shown on both thefungal和theplantside. The plants siRNA activity has already widely used in plant science through techniques like Host-induced Gene Silencing (HIGS) in order to decrypt plant biology at the molecular level. In recent years, more and more efforts have been made to adapt siRNA for use in crop protection.

siRNA和抗真菌抗性

siRNAs are frequently used by fungal pathogens of plants, but also of mammals, likeMucor Circinelloides，机会主义的病原体。It has previously been shown那M.Circinelloidescan develop a transient resistance to the antifungal drug FK506 through RNA-interference, leading to silencing of the fungicide target gene.

In addition, scientists from the Duke University (USA) have shown that resistance to another fungicide (5-FOA) happens without mutations in the target genes,pyrf和pyrg(unpublished data presented during the congress). This resistance appears to be controlled, like resistance to FK506, by expression of siRNAs against the antifungal drug target genes, providing priceless clues about antifungal drug resistance mediated by siRNAs.

siRNAs and mycotoxins

siRNAs are also involved in the production of mycotoxins; toxic secondary metabolites secreted by fungi during plant-fungi interactions. Mycotoxins are a major contaminant on crops and some of them can cause severe diseases in humans, including cancer.

Mycotoxins are a major contaminant on crops and some of them can cause severe diseases in humans, including cancer.

使用HIGS，可以解释SRNA如何影响脱氧基因烯醇（DON）的产生，这是小麦病原体产生的农艺上重要的霉菌毒素镰刀菌。这些发现具有重要的含义，这可能会导致一种新的生态友好方法来控制植物致病真菌的霉菌毒素的产生。

The most promising and exciting progress in siRNA research has been made by scientists from the University of California (USA).他们强调了双向跨语对话via siRNAs between phytopathogenic fungi and their host plant. They showed that siRNAs are widely used by辣椒灰感染1000多个寄主植物。这些siRNA被易位在植物细胞内，绕过植物防御系统，并构成了一类新型的效应蛋白参与感染。

But above all, it was shown that an拟南芥plant expresses siRNA which targetsB. cinerea在RNAi基因,能够规避真菌开发。这一发现使这些科学家开发了喷雾诱导的基因沉默（SIGS）方法。看来，通过在通常对真菌感染的植物上应用合成siRNA，您可以帮助这些植物更好地抵抗感染。

看来，通过在通常对真菌感染的植物上应用合成siRNA，您可以帮助这些植物更好地抵抗感染。

This finding has two potential openings. Firstly, a biotechnological tool could be made to silence fungal genes without the use of systems that are genetically tractable to vary gene expression, just by applying synthetic siRNAs under lab conditions. Secondly, a new way to control fungal epidemics in field could be developed through the dissemination of synthetic siRNAs by spray.

sirnas的未来

植物和真菌siRNA为生物技术和作物管理方面的许多工具开辟了道路。通过喷雾siRNAS的分散剂可以解决其他控制方法带来的许多问题。重要的是，这可能是环保控制真菌疾病的方式of crops, compared to the shockingly expensive cost of synthetic fungicides at the ecological scale.

但是，如果这些合成的siRNA真的“环保”，这尚待阐明：它们能否通过该领域的其他生物体中的非特异性沉默来影响环境？还是它们会影响人类健康？在将这种疗法广泛应用于农作物之前，这些问题仍有待解决。