Integrated Phloem Sap mRNA and Protein Expression Analysis Reveals Phytoplasma-infection Responses in Mulberry

Area of Science:

• Plant Pathology
• Molecular Biology
• Biochemistry

Background:

• Phytoplasma infections pose significant threats to mulberry production.
• Understanding plant responses at the molecular level is crucial for developing resistance strategies.

Purpose of the Study:

• To investigate the molecular changes in mulberry phloem sap in response to phytoplasma infection.
• To identify key genes and proteins involved in mulberry's defense mechanisms.

Main Methods:

• Comparative analysis of mRNA and protein expression profiles in healthy and infected mulberry phloem sap.
• Gene expression analysis, including induction by pathogen inoculation and response to jasmonic acid.
• Ectopic expression studies in *Arabidopsis thaliana* to assess resistance conferred by *MuMLPL329*.

Main Results:

• Identified 955 differentially expressed unigenes and 136 differentially expressed proteins.
• Observed significant upregulation of the major latex protein-like 329 (*MuMLPL329*) gene and its protein in infected phloem.
• *MuMLPL329* expression enhances resistance in *Arabidopsis* against *Botrytis cinerea*, *Pseudomonas syringae* pv tomato DC3000, and phytoplasma.

Conclusions:

• Phytoplasma infection triggers complex molecular responses in mulberry phloem, involving signaling, hormone metabolism, and stress responses.
• *MuMLPL329* plays a critical role in enhancing plant defense, potentially by modulating defense gene expression and flavonoid content.
• The identified differentially expressed molecules offer insights into mulberry's phytoplasma resistance mechanisms and potential disease symptoms.