Intraspecies variation in cotton border cell production: rhizosphere microbiome implications

Area of Science:

• Plant Biology
• Root Development
• Plant-Microbe Interactions

Background:

• Border cells, specialized cells from the root cap, constitute over 90% of carbon exudates in the rhizosphere.
• These cells are hypothesized to function in root tip defense via an extracellular trapping mechanism, analogous to mammalian white blood cells.
• Limited intraspecies variation in border cell production has previously hindered studies on their impact on crop yields.

Purpose of the Study:

• To investigate intraspecific variation in border cell production among cotton cultivars.
• To assess the functional differences in extracellular trap formation and bacterial trapping in response to defense elicitors.
• To establish a basis for studying the role of border cells in plant development and the rhizosphere.

Main Methods:

• Compared border cell number, viability, and clumping across 22 cotton cultivars.
• Assessed slime layer/extracellular trap production induced by copper chloride in two contrasting cultivars.
• Quantified bacterial trapping efficiency by border cells in these selected cultivars.

Main Results:

• Observed significant variation in border cell production, with some cultivars producing over 20,000 cells per root, a 100% increase over prior reports.
• No significant differences were found in border cell morphology, viability, or clumping.
• While extracellular trap formation was similar, bacterial trapping capacity was reduced in a high-border-cell-producing cultivar compared to a lower-producing one.

Conclusions:

• Intraspecific variation in border cell production in cotton offers a valuable tool for laboratory, greenhouse, and field studies on their developmental impact.
• Further research is warranted to elucidate the genetic and environmental factors driving this variation.
• Understanding this variation is crucial for deciphering its influence on rhizosphere community structure and plant health.