The rice nuclear gene WLP1 encoding a chloroplast ribosome L13 protein is needed for chloroplast development in rice grown under low temperature conditions

Abstract

Plastidial ribosome proteins (PRPs) form the major component of the plastidial ribosome. Here we describe a rice mutant named wlp1 (white leaf and panicles 1) selected from a population of tissue culture regenerants. The early seedling leaves of the mutant were albino, as was the immature panicle at heading, and the phenotype was more strongly expressed in plants exposed to low temperature conditions. Changes in the leaf pigmentation of the mutant were due to altered chlorophyll content and chloroplast development. Positional cloning of WLP1, followed by complementation and knock-down experiments, showed that it encodes a 50S ribosome L13 protein. The WLP1 protein localized to the chloroplast. WLP1 was mainly transcribed in green tissues and particularly abundantly in the early seedling leaves. In addition, the expression level of WLP1 was induced by the low temperature. The transcription pattern of a number of genes involved in plastidial transcription/translation and in photosynthesis was altered in the wlp1 mutants. These results reveal that WLP1 is required for normal chloroplast development, especially under low temperature conditions. This is the first report on the function of PRPs in rice.

Characterization and fine mapping of a new early leaf senescence mutant es3(t) in rice

“…The relative expression level of each transcript was compared with that of Actin1 which was selected as the internal standard for all leaf samples. The photosynthesis-associated genes (rbcL, rbcS , psaA, psbA, CAB1R, CAB2R, HEMA1, PORA and CAO) (Song et al 2014;Tan et al 2014), senescence-associated transcription factors (OsWRKY23, OsWRKY72 and OsNAC2), senescence-associated genes (Osl2, Osl30, Osl43, Osl57, Osl85, Osh36 and Osh69) , and ABA synthesis-related genes (OsNCED1, OsNCED2, OsNCED3, OsNCED4, OsNCED5) (Zhu et al 2009) were analyzed in wild-type plant (WYJ7) and es3(t) mutant.The specific primers used for the quantification of these genes are listed in Supplemental Table 3. primers were subsequently used to screen 728 individual genotypes, and we further delimited the ES3(t) locus to an interval of 35-kb DNA region between the STS markers HK17-23 and HK17-30 on the bacterial artificial clone AC097624 (BAC1) (Fig. 2b, c).…”

Temperature-sensitive albino geneTCD5, encoding a monooxygenase, affects chloroplast development at low temperatures

“…Disruption of the rice genes OsV4 and YSA encoding pentatricopeptide repeat proteins caused a seedling-specific albino phenotype at low temperatures (Su et al , 2012; Gong et al , 2014). WLP1 encodes a 50S chloroplast ribosome L13 protein and is necessary for chloroplast development in rice; however, the leaf and immature panicle of its mutant are albino at low temperatures (Song et al , 2014). …”

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

“…Environmental low temperature arrests protein synthesis by causing ribosomal pausing (Grennan and Ort, 2007) or retardation of ribosomal biogenesis and RNA processing (Millerd et al, 1969; Hopkins and Elfman, 1984; Barkan, 1993). Furthermore, loss of translational factors such as ribosomal protein (Rogalski et al, 2008; Fleischmann et al, 2011; Ehrnthaler et al, 2014; Song et al, 2014), translation elongation factor (Liu et al, 2010), rRNA methylase (Tokuhisa et al, 1998) and the RNA binding protein required for RNA processing (Kupsch et al, 2012) leads to sensitivity to low temperatures. These reports suggest the existence of a particular mechanism that protects chloroplast translation against cold stress, which can be expected to be associated with NUS1 , V 2 , V 3 , and ST1 .…”

“…Recently, several other genes have been isolated from low temperature-conditional, chloroplast-deficient mutants of rice, such as OsV4 ( virescent 4 ), wlp1 ( white leaf and panicles 1 ), and tcd9 ( thermo-sensitive chloroplast development 9 ; Gong et al, 2014; Jiang et al, 2014; Song et al, 2014). The corresponding genes in OsV4 , wlp1 , and tcd9 mutants encode plastidial pentatricopeptide repeat (PPR) protein, plastid ribosomal protein L13, and a subunit of chaperonin 60 (CP60α) required for chloroplast division, respectively.…”

“…The corresponding genes in OsV4 , wlp1 , and tcd9 mutants encode plastidial pentatricopeptide repeat (PPR) protein, plastid ribosomal protein L13, and a subunit of chaperonin 60 (CP60α) required for chloroplast division, respectively. Similarly to NUS1 , V 2 , V 3 , and ST1 , their functions are speculated to be involved in early chloroplast development at low temperatures (Gong et al, 2014; Jiang et al, 2014; Song et al, 2014). It is possible that these factors are involved in a closely related mechanism to chloroplast protein expression and assembly, which is required at low temperatures, but not essential for chloroplast development during early leaf development at higher temperatures.…”