Development of expressed sequence tag and expressed sequence tag-simple sequence repeat marker resources for Musa...

Area of Science:

• Plant genomics
• Molecular biology
• Crop science

Background:

• Banana (Musa acuminata) is vital for global food security but susceptible to diseases like Black Leaf Streak Disease (BLSD).
• Limited genetic diversity and sterility hinder the development of disease-resistant banana varieties.
• Understanding banana-Mycosphaerella fijiensis (Mf) interactions is crucial for managing BLSD.

Purpose of the Study:

• To create an expressed sequence tag (EST) database for transcripts involved in banana-Mf interactions.
• To develop microsatellite (simple sequence repeat - SSR) markers for banana genetic improvement.
• To identify genetic resources for enhancing banana resistance to biotic stresses.

Main Methods:

• cDNA libraries were constructed from resistant (MAC4) and susceptible (MACV) banana leaves after Mf infection.
• ESTs were sequenced, assembled, and annotated using bioinformatic tools (TGICL, BLAST, Blast2GO, InterProScan).
• Simple sequence repeats (SSRs) were identified using Mreps, and marker polymorphism was evaluated across M. acuminata accessions.

Main Results:

• Over 9,300 high-quality ESTs were generated, assembling into nearly 4,000 unigenes, with over 2,500 annotated.
• Gene ontology (GO) and pathway analyses provided insights into functional gene categories.
• 624 SSR loci were identified, with 75 markers showing polymorphism across 20 M. acuminata accessions, yielding 289 alleles.

Conclusions:

• The developed EST collection serves as a valuable resource for studying functional genes in banana-Mf interactions.
• The identified SSR markers are applicable for genetic mapping and diversity studies in banana.
• These resources will support marker-assisted breeding for improved banana disease resistance.