Water Stress and Shade Elicit Similar Convergent Responses in Maize Kernel Development and Gene Expression During...

Area of Science:

• Plant Science
• Agricultural Science
• Molecular Biology

Background:

• Maize (Zea mays) yield is significantly reduced by drought during early kernel development.
• Photosynthate-limiting stresses like high plant density and shade also negatively affect kernel development.

Purpose of the Study:

• To investigate how water stress (WS) and shade influence maize kernel development.
• To understand the molecular mechanisms underlying stress responses in kernel tissues.

Main Methods:

• Maize plants were subjected to controlled water stress and shade conditions from 1 to 9 days after pollination.
• Evapotranspiration, root growth, carbohydrate and abscisic acid (ABA) levels were measured.
• RNA sequencing (RNA-seq) was used to profile gene expression in kernel tissues.

Main Results:

• Severe water stress (WS) increased root development, while shade decreased it.
• Both severe WS and shade elevated ABA levels in kernel tissues.
• Shared gene expression patterns in pedicel-placenta tissue under severe WS and shade suggest a common regulatory pathway involving ABA, carbohydrates, trehalose, and ethylene.

Conclusions:

• The pedicel-placenta tissue shows similar ABA accumulation and gene expression responses to severe water stress and shade.
• This suggests a critical role for the pedicel-placenta in mediating maize kernel set decisions under stress.