Do seed VLCFAs trigger spongy tissue formation in Alphonso mango by inducing germination?

Area of Science:

• Plant Physiology
• Biochemistry
• Fruit Science

Background:

• Spongy tissue (ST) is a physiological disorder in Alphonso mangoes, making them inedible.
• ST is associated with germination-associated events during fruit maturation and inter-fruit competition.
• Reduced fat content in ST-affected fruits suggests a link to lipid metabolism.

Purpose of the Study:

• To investigate the association between seed fat content and spongy tissue formation in Alphonso mangoes.
• To understand the role of specific fatty acids in the development of ST.
• To identify biochemical triggers for ST during pre-harvest fruit growth.

Main Methods:

• Analysis of fat content in whole fruit and seeds during different stages of maturity.
• Quantification of fatty acids, including very long chain fatty acids (VLCFAs), in seeds.
• Measurement of plant hormone levels (cytokinin, gibberellins, abscisic acid) in seeds.
• Assessment of fatty acid ratios and membrane integrity in fruit pulp.

Main Results:

• Seed fat content decreased significantly in ST-affected fruits, particularly tetracosanoic and hexacosanoic acids.
• Increased linolenic acid and decreased oleic acid in seeds correlated with pre-germination events.
• Hormonal changes (increased cytokinin/gibberellins, decreased abscisic acid) in seeds indicated germination onset.
• Reduced linolenic/linoleic acid ratio in pulp led to membrane damage and spongy tissue formation.

Conclusions:

• Reduced biosynthesis of VLCFAs in mango seeds during fruit growth may initiate pre-germination events.
• Biochemical changes in the pulp, including lipid peroxidation, result from seed alterations, culminating in ST.
• VLCFAs play a critical role in inducing spongy tissue formation in Alphonso mangoes pre-harvest.