Pathogenesis-related (PR) proteins and antimicrobial peptides (AMPs) are a group of diverse molecules that are induced by phytopathogens as well as defense related signaling molecules. They are the key components of plant innate immune system especially systemic acquired resistance (SAR), and are widely used as diagnostic molecular markers of defense signaling pathways. Although, PR proteins and peptides have been isolated much before but their biological function remains largely enigmatic despite the availability of new scientific tools. The earlier studies have demonstrated that PR genes provide enhanced resistance against both biotic and abiotic stresses, which make them one of the most promising candidates for developing multiple stress tolerant crop varieties. In this regard, plant genetic engineering technology is widely accepted as one of the most fascinating approach to develop the disease resistant transgenic crops using different antimicrobial genes like PR genes. Overexpression of PR genes (chitinase, glucanase, thaumatin, defensin and thionin) individually or in combination have greatly uplifted the level of defense response in plants against a wide range of pathogens. However, the detailed knowledge of signaling pathways that regulates the expression of these versatile proteins is critical for improving crop plants to multiple stresses, which is the future theme of plant stress biology. Hence, this review provides an overall overview on the PR proteins like their classification, role in multiple stresses (biotic and abiotic) as well as in various plant defense signaling cascades. We also highlight the success and snags of transgenic plants expressing PR proteins and peptides.

致病相关（PR）蛋白和抗菌肽（AMPs）是一组由植物病原体以及防御相关信号分子诱导的多种分子。它们是植物固有免疫系统特别是系统获得性抗性（SAR）的关键组成部分，被广泛用作防御信号通路的诊断分子标记。虽然，PR蛋白和多肽早已被分离出来，但是尽管有新的科学工具，但它们的生物学功能仍然很大程度上是个谜。较早的研究表明，PR基因对生物和非生物胁迫均具有增强的抗性，使其成为开发多种耐逆性作物品种的最有希望的候选者之一。在这方面，植物基因工程技术被广泛认为是使用不同的抗微生物基因（如PR基因）开发抗病转基因作物的最引人入胜的方法之一。单独或组合使用PR基因（几丁质酶，葡聚糖酶，索马甜，防御素和硫蛋白）的过表达大大提高了植物对多种病原体的防御反应水平。然而，调控这些多功能蛋白质表达的信号传导途径的详细知识对于改善作物植物承受多种胁迫至关重要，这是植物胁迫生物学的未来主题。因此，本综述提供了有关PR蛋白的总体概述，例如它们的分类，在多种胁迫（生物和非生物）中的作用以及在各种植物防御信号级联反应中的作用。