Overexpression of OsGATA12 regulates chlorophyll content, delays plant senescence and improves rice yield under high density planting

Abstract

Agronomic traits controlling the formation, architecture and physiology of source and sink organs are main determinants of rice productivity. Semi-dwarf rice varieties with low tiller formation but high seed production per panicle and dark green and thick leaves with prolonged source activity are among the desirable traits to further increase the yield potential of rice. Here, we report the functional characterization of a zinc finger transcription factor, OsGATA12, whose overexpression causes increased leaf greenness, reduction of leaf and tiller number, and affects yield parameters. Reduced tillering allowed testing the transgenic plants under high density which resulted in significantly increased yield per area and higher harvest index compared to wild-type. We show that delayed senescence of transgenic plants and the corresponding longer stay-green phenotype is mainly due to increased chlorophyll and chloroplast number. Further, our work postulates that the increased greenness observed in the transgenic plants is due to more chlorophyll synthesis but most significantly to decreased chlorophyll degradation, which is supported by the reduced expression of genes involved in the chlorophyll degradation pathway. In particular we show evidence for the down-regulation of the STAY GREEN RICE gene and in vivo repression of its promoter by OsGATA12, which suggests a transcriptional repression function for a GATA transcription factor for prolonging the onset of senescence in cereals.

Characterization of the GATA gene family in Vitis vinifera: genome-wide analysis, expression profiles, and involvement in light and phytohormone response

“…and AtGATA16, which participate in greening, hypocotyl elongation, phyllotaxy, floral organ initiation, accessory meristem formation, flowering time, and senescence (Ranftl et al 2016). Likewise, the orthologous gene in rice, OsGATA12, regulates chlorophyll levels, senescence, and yield parameters (Lu et al 2017). These results suggest that In grape berry tissues, some VvGATA genes in subgroup III displayed higher D r a f t expression than the other VvGATA genes according to our RNA-seq data (Fig.…”

“…In monocot rice, NL1 plays an important role in organ differentiation and reproductive development (Wang et al 2009). OsGATA12 regulates chlorophyll content, senescence, and yield in D r a f t rice (Lu et al 2017). In woody plant species, poplar GATA transcription factor PdGNC regulates chloroplast ultrastructure and photosynthesis (An et al 2014).…”

Transcriptome Analysis of a Premature Leaf Senescence Mutant of Common Wheat (Triticum aestivum L.)

“…Chlorophyll synthesis-related genes, such as orthologs of At5G54190 , At1G44446 and At3G51820 genes, were reduced in m68 . GATA transcription factors can influence leaf senescence by regulating the chlorophyll content [ 17 , 18 , 19 , 20 ]. In our study, the GATA zinc finger family genes MSTRG.14332.1 and MSTRG.4134 8.1 were down-regulated during leaf senescence, which agrees with the function of GATA transcription factors.…”

“…In soybean, the over-expression of GmGATA44 can rescue the phenotype of the A. thaliana gnc mutant by reversing a deficiency in the chlorophyll content [ 18 ]. Overexpression of the GATA-zinc transcription factor OsGATA12 can delay senescence and enhance rice yield by elevating the chlorophyll content of leaves [ 19 ]. Additionally, Cytokinin responsive GATA transcription factor 1 ( Cga1 ) has been reported to influence plant architecture by regulating the chlorophyll content in rice [ 20 ].…”

SiYGL2 Is Involved in the Regulation of Leaf Senescence and Photosystem II Efficiency in Setaria italica (L.) P. Beauv.

“…For cereal crops, leaf senescence provides most of the nitrogen in grains. It has been reported that delayed senescence could lead to high yields ( Lu et al, 2017 ) because the filling period is prolonged and sugar and nitrogen accumulation is increased ( Egli, 2011 ; Gregersen et al, 2013 ). Conversely, grain quality has negative correlations with senescence progression.…”