Establishment of the chloroplast genetic system in rice during early leaf development and at low temperatures

Abstract

Chloroplasts are the central nodes of the metabolic network in leaf cells of higher plants, and the conversion of proplastids into chloroplasts is tightly coupled to leaf development. During early leaf development, the structure and function of the chloroplasts differ greatly from those in a mature leaf, suggesting the existence of a stage-specific mechanism regulating chloroplast development during this period. Here, we discuss the identification of the genes affected in low temperature-conditional mutants of rice (Oryza sativa). These genes encode factors involved in chloroplast rRNA regulation (NUS1), and nucleotide metabolism in mitochondria, chloroplasts, and cytosol (V2, V3, ST1). These genes are all preferentially expressed in the early leaf developmental stage P4, and depleting them causes altered chloroplast transcription and translation, and ultimately leaf chlorosis. Therefore, it is suggested that regulation of cellular nucleotide pools and nucleotide metabolism is indispensable for chloroplast development under low temperatures at this stage. This review summarizes the current understanding of these factors and discusses their roles in chloroplast biogenesis.

The Rice Pentatricopeptide Repeat Gene TCD10 is Needed for Chloroplast Development under Cold Stress

“…As described previously, the processes accompanying chloroplast development can be divided into three phases (Mullet 1993; Kusumi et al 2010 and 2014). It is clearly known that OsPOLP1 , encoding one plastidial DNA polymerase (Takeuchi et al 2007; Kusumi et al 2010), FtsZ encoding a component of the plastid division machinery (Vitha et al 2001) are critical for the first phase, determine the number and size of chloroplasts (Takeuchi et al 2007) and the NEP-transcribed genes which encode PEP cores (e.g.…”

“…Chloroplasts are mostly allocated in the leaves of plants, and its development is closely linked with the leaf development. As known, plastid development from proplastids to mature chloroplasts can be divided into three phases (Chory et al 1991; Mullet 1993; Kusumi et al 1997 and 2014). The first phase concerns the activation of plastid replication and plastid DNA synthesis.…”

Cytogenetic Analyses of PSL1 Mutant, a Novel Low‐Temperature‐Sensitive Purple‐Striped Leaf Color Mutant in Wheat

“…A number of genes that regulate leaf color variation have been identified and cloned using leaf color mutants in Arabidopsis Heynh. The phenotype of these mutants is normal or near normal at permissive temperatures, but mutational phenotypes are found at lower temperatures (Kusumi and Iba, 2014). Beauv.…”

“…However, the molecular mechanisms that allow crops to tolerate low-temperature stress are not well understood (Mock and Valentin, 2004). One type is sensitive to a restrictive temperature of ?20°C, such as many tropical and subtropical plants including rice (Kusumi and Iba, 2014). One type is sensitive to a restrictive temperature of ?20°C, such as many tropical and subtropical plants including rice (Kusumi and Iba, 2014).…”

“…There are two known types of low-temperature-sensitive leaf color mutants in plants. One type is sensitive to a restrictive temperature of ?20°C, such as many tropical and subtropical plants including rice (Kusumi and Iba, 2014). The characteristics of these low-temperature-sensitive leaf color mutants are generally controlled by single recessive nuclear genes (Tan et al, 2014;Liu et al, 2015).…”