Physiological mechanism underlying spikelet degeneration in rice

Abstract

The phenomenon of degenerated spikelets is very common in cereals, and considered as a serious physiological defect and a main constraint to grain production. Understanding the physiological mechanism in which spikelet degeneration occurs would have great significance in enhancing yield potential in grain crops. Taking rice as an example, the paper reviewed the physiological mechanism underlying spikelet degeneration, with focus on the roles of phytohormones in regulating the process. There are several hypotheses for the spikelet degeneration, such as resource limitation, self-organization, and primigenic dominance. However, convincing evidences are lack to support the assumptions. Phytohormones including auxins, cytokinins, gibberellins, abscisic acid, and ethylene are involved in regulating spikelet degeneration in cereals. The new phytohormones of brassinosteroids and polyamines have been observed to suppress spikelet degeneration in rice. The interactions among or between plant hormones may play a more important role in regulating spikelet degeneration. However, the information on such interactions is very limited. Some agronomic practices, especially proper water and nitrogen management, could reduce spikelet degeneration but the mechanism underlying remains unclear. Further research is needed to understand the cross-talk among/between phytohormones on spikelet degeneration, to reveal the physiological and molecular mechanism in which phytohormones and their interactions regulate the degeneration of spikelets, to exploit approaches to decrease spikelet degeneration and to elucidate their mechanism.

DEGENERATED PANICLE AND PARTIAL STERILITY 1 (DPS1) encodes a cystathionine β‐synthase domain containing protein required for anther cuticle and panicle development in rice

“…Panicle apical abortion and reduced fertility are common reasons of low seed‐setting rate in rice (Heng et al ., ; Yang et al ., ). Several environmental and physiological factors contribute to the panicle apical degeneration and reduced fertility, such as unfavorable climatic conditions (Yao et al ., ; Cheng et al ., ), hormonal imbalance (Z. Wang et al ., ), and nutrient deficiency (Durbak et al ., ; Heng et al ., ). Previously, three mutants, namely totou1 , paa1 and spl6 , related to panicle apical degeneration have been characterized.…”

Of floral fortune: tinkering with the grain yield potential of cereal crops

“…Ts1 encodes a plastid‐targeted lipoxygenase that catalyzes the first dedicated step in JA biosynthesis, which is the peroxidation of alpha‐linolenic acid to (13 S )‐hydroperoxyoctadecatrienoic acid. Whether JA or any other hormone is involved in, for example, barley row‐type determination and lateral floret abortion is not established, but hormonal effects represent an exciting topic for future research on improving floret fertility in cereal crops (Wang et al ., ).…”

Peer Review #2 of "Comparative transcriptome analysis of panicle development under heat stress in two rice (Oryza sativa L.) cultivars differing in heat tolerance (v0.1)"

“…BGIOSGA014915, which participates in BR synthesis, was downregulated in RHR. Previous reports have found that BRs can modulate the metabolic responses of plants to abiotic environmental stresses (Vriet et al 2012;Wang et al 2018). BR accumulation reportedly reduces spikelet degeneration under nitrogen application (Zhang, 2018).…”