Bakteriyel patojenlere karşı bitkilerdeki dayanıklılık mekanizmaları

Son yıllarda yapılan çalışmalar, bitki ve patojen arasındaki moleküler etkileşim mekanizmalarını ortaya çıkarmıştır. Bitki bağışıklık sistemi, patojen veya mikropla ilgili moleküler yapılar (PAMP’lar veya MAMP’lar) tarafından harekete geçirilir. Farklı PAMP’lar genellikle bitkilerdeki farklı tanılayıcı hücre yüzey reseptörleri (PRR’ler) tarafından algılanır ve bağışıklık sistemi için hücrelerarası sinyal iletişimi aktive edilir. Ancak patojenler, PAMP’a dayalı bağışıklık sistemini baskılamak için çok sayıda virulens faktörleri geliştirirler. Gram negatif bitki patojeni bakterilerin çoğu, virulens özellikteki efektör proteinlerini konukçu hücresine aktarmak için tip III salgı sistemine sahiptirler. Bu efektör proteinler bitki bağışıklık sistemini engeller ve hastalık gelişimini teşvik eder. Diğer taraftan bitkiler ise patojenlere karşı ikinci bir bağışıklık sistemine sahiptir. Özellikle bazı bitkiler, efektöre dayalı harekete geçen bağışıklık sisteminde efektör proteinleri etkili bir şekilde inaktive eden ve hücrelerarasında bulunan hastalığa karşı dayanıklılık sağlayan özel proteinlere (R proteinlerine) sahiptir.

Plant resistance mechanisms to bacterial pathogens

Recent studies have presented molecular interaction mechanisms between plant and pathogen. The plant innate immunity system is triggered by the pathogen or microbe associated molecular patterns (PAMPs/MAMPs). Different PAMPs are often perceived by distinct cell surface pattern-recognition receptors (PRRs) and activate intracellular signaling pathways in plant cells for immunity system. However, pathogens have evolved multiple virulence factors to suppress PAMP-triggered immunity. Most of gram negative plant pathogenic bacteria have the type III secretion system to transfer of virulence effector proteins into host cell. These effector proteins inhibit plant immunity system and support pathogenesis. On the other hand, plants have the secondary plant innate immunity system against pathogens. Especially, some plants have the specific intracellular disease resistance (R) proteins which effectively inactivate virulence effectors in effector-triggered immunity system.

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