Suppressor of rid1 (SID1) shares common targets with RID1 on florigen genes to initiate floral transition in rice

Abstract

The transition from vegetative to reproductive growth is a critical process in the life cycle of higher plants. Previously, we cloned Rice Indeterminate 1 (RID1), which acts as the master switch for the transition from the vegetative to reproductive phase in rice. Although the photoperiod pathway of RID1 inducing expression of the florigen genes Hd3a and RFT1 via Ehd1 has been established, the alternative pathways for the essential flowering transition need to be further examined. Here, we identified a Suppressor of rid1 (SID1), which rescues the never-flowering phenotype of rid1. SID1 encodes an INDETERMINATE DOMAIN (IDD) transcription factor. Mutation in SID1 showed the delayed flowering phenotype. Gain-of-function of SID1, OsIDD1, or OsIDD6 could restore the rid1 to flowering. Further analyses showed SID1 and RID1 directly target the promoter regions of Hd3a and RFT1, two florigen genes in rice. Taken together, our results reveal an autonomous flowering pathway might be mediated by RID1, thereby controlling the phase transition from vegetative to reproductive development in rice.

Overexpression of OsFTL10 induces early flowering and improves drought tolerance in Oryza sativa L.

“…Furthermore, photoperiodic flowering in rice is considered as two distinct pathways: one including OsGI (an orthologue of Gigantea ), Hd1 (Heading date 1) and Hd3a. These proteins form a pathway of OsGI-Hd1-Hd3a, which is similar to that of Arabidopsis under SD conditions (Turck, Fornara & Coupland, 2008; Deng et al, 2017). Another one including Ghd7 (Grain Number, Plant Height and Heading Date 7), Ehd1 (Early heading date 1) and Hd3a/RFT1.These proteins form a pathway of Ghd7-Ehd1-Hd3a/RFT1 in rice under LD conditions.…”

Meta-QTL and ortho-MQTL analyses identified genomic regions controlling rice yield, yield-related traits and root architecture under water deficit conditions

“…The rice genomic region subtending MQTL-PH7 harbors the NAL1 gene as a regulator of PH 55 : we identified the ortholog of this gene ( Zm00001d026296 ) in the maize ortho-MQTL. In the syntenic region of rice MQTL-YLD2 on chromosome 5 of maize, there were two MQTLs (mQTL_GY_5 86 , MQTL5.7 17 ) containing the orthologs of OsALMT7 and SID1 genes ( Zm00001d017571 and Zm00001d017560 ), known to affect YLD in rice 62 , 88 . The orthologous gene of TAC3 in maize ( Zm00001d033857 ) in the syntenic region of MQTL-YLD3 in maize (mQTL_GY_1b) regulates tiller angle that might affect YLD under water deficit conditions 63 .…”

Role of the INDETERMINATE DOMAIN Genes in Plants

“…Most IDD genes have been mainly characterized in Arabidopsis; however, a few have been functionally characterized in other plants (Table 1). They are involved in seed maturation and germination, GA signaling, root development, sugar metabolism, leaf polarity, starch metabolism, cold-stress signaling, auxin biosynthesis and transport, flowering, plant architecture, shoot gravitropism, ammonium uptake, and endosperm development (Figure 7) [4,5,7,8,9,25,32,36,42,43,44,47,48,53,54,55,75,77,78,79,80,81,82]. IDD activity regulates many traits that have a direct or indirect impact on crop yield.…”

“…These results indicate that sugar status linked to T6P signaling is vital for flowering [31]. In rice, OsIDD1 and OsIDD6 overexpression rescue the late-flowering phenotype of rice Ehd2 , illustrating that IDD family genes might have a functional redundancy in sugar metabolism and the control of flowering time [32]. These reports suggest that multiple IDD genes modulate sugar metabolism, and some of them have a direct or indirect link with flowering regulation (Figure 5).…”