Integration of embryo-endosperm interaction into a holistic and dynamic
picture of seed development using a rice mutant with notched-belly
grains
Abstract
Embryo-endosperm interaction strongly affects the developmental process
of seeds and hence the formation of crop yield and quality. However,
signals that orchestrate developmental processes of the two compartments
are largely unknown. This study aims to provide an integrative landscape
of rice seed development by organizing the information about
embryo-endosperm interaction. Using a mutant with notched-belly grains,
we devised a novel comparison method that can quantitatively evaluate
the effect of embryo on the developmental process of endosperm, by
comparing the upper and bottom endosperms of the mutant. Global
comparison of mRNAs datasets in embryo and endosperm samples collected
from 5 DAF (day after fertilization) through maturity uncovered a
dragging effect of embryo on the developmental transition of the
endosperm, extending the middle stage and delaying the late stage.
Biochemical analysis revealed that signaling pathways of T6P-SnRK1, and
GA or IAA may be involved in mediating this developmental transition.
Integrating the information about embryo-endosperm bidirectional
dialogue enables a new rice seed developmental staging system to be
proposed. The results obtained should be valuable for elucidating the
biological processes and signatures of grain formation, hence providing
a valuable resource for modifying the molecular and physiological
processes responsible for cereal grain yield and quality.