The majority of agronomic traits are controlled by multiple genes that cause minor phenotypic effects, making the identification of these genes difficult Here we introduce MutMap, a method based on whole-genome resequencing of pooled DNA from a segregating population of plants that show a useful phenotype In MutMap, a mutant is crossed directly to the original wild-type line and then selfed, allowing unequivocal segregation in second filial generation (F(2)) progeny of subtle phenotypic differences This approach is particularly amenable to crop species because it minimizes the number of genetic crosses (n = 1 or 0) and mutant F(2) progeny that are required We applied MutMap to seven mutants of a Japanese elite rice cultivar and identified the unique genomic positions most probable to harbor mutations causing pale green leaves and semidwarfism, an agronomically relevant trait These results show that MutMap can accelerate the genetic improvement of rice and other crop plants

/pdf/genome-sequencing-reveals-agronomically-important-loci-in-2v1h9yey4q.pdf

Genome sequencing reveals agronomically important loci in rice using MutMap

We made a series of improved Gateway binary vectors (pGWBs) for plant transformation. Fifteen different reporters and tags, sGFP, GUS, LUC, EYFP, ECFP, G3GFP, mRFP, 6xHis, FLAG, 3xHA, 4xMyc, 10xMyc, GST, T7, and TAP, were employed. Some vectors carry the 2x35S-Omega promoter for higher-level expression. The kanamycin- and hygromycin-resistant markers are independently available for each of the 43 types of vectors, thus an additional transformation of once-transformed plants can be carried out easily. Their small size and high-copy number in Escherichia coli make possible easier handling at plasmid preparation and sequencing. Improved pGWBs should be a powerful tool for transgenic research in plants.

/pdf/improved-gateway-binary-vectors-high-performance-vectors-for-3chslf16sh.pdf

Improved Gateway binary vectors: high-performance vectors for creation of fusion constructs in transgenic analysis of plants.

RNA-Guided Genome Editing in Plants Using a CRISPR–Cas System

Plant growth is coordinately regulated by environmental and hormonal signals. Brassinosteroid (BR) plays essential roles in growth regulation by light and temperature, but the interactions between BR and these environmental signals remain poorly understood at the molecular level. Here, we show that direct interaction between the dark- and heat-activated transcription factor phytochrome-interacting factor 4 (PIF4) and the BR-activated transcription factor BZR1 integrates the hormonal and environmental signals. BZR1 and PIF4 interact with each other in vitro and in vivo, bind to nearly 2,000 common target genes, and synergistically regulate many of these target genes, including the PRE family helix-loop-helix factors required for promoting cell elongation. Genetic analysis indicates that BZR1 and PIFs are interdependent in promoting cell elongation in response to BR, darkness or heat. These results show that the BZR1-PIF4 interaction controls a core transcription network, enabling plant growth co-regulation by the steroid and environmental signals.

/pdf/interaction-between-bzr1-and-pif4-integrates-brassinosteroid-3q3nv3as0b.pdf

Interaction between BZR1 and PIF4 integrates brassinosteroid and environmental responses

Florigen, a plant hormone that translocates from leaves to the shoot apex to induce flowering, is encoded by the FLOWERING LOCUS T (FT) gene. The detailed molecular mechanism for florigen action and the identity of its receptors remained unknown. Ko Shimamoto and colleagues show that in rice, florigen binds to 14-3-3 proteins, a type of regulatory molecule present in all eukaryotic cells, and to the transcription factor OsFD1. The crystal structure of the resulting florigen activation complex (FAC) has been determined, providing a mechanistic basis for florigen function in flowering. This work offers clues for improving agriculturally important traits by manipulating florigen and its regulators. ‘Florigen’ was proposed 75 years ago1 to be synthesized in the leaf and transported to the shoot apex, where it induces flowering. Only recently have genetic and biochemical studies established that florigen is encoded by FLOWERING LOCUS T (FT), a gene that is universally conserved in higher plants2,3,4. Nonetheless, the exact function of florigen during floral induction remains poorly understood and receptors for florigen have not been identified. Here we show that the rice FT homologue Hd3a5 interacts with 14-3-3 proteins in the apical cells of shoots, yielding a complex that translocates to the nucleus and binds to the Oryza sativa (Os)FD1 transcription factor, a rice homologue of Arabidopsis thaliana FD. The resultant ternary ‘florigen activation complex’ (FAC) induces transcription of OsMADS15, a homologue of A. thaliana APETALA1 (AP1), which leads to flowering. We have determined the 2.4 A crystal structure of rice FAC, which provides a mechanistic basis for florigen function in flowering. Our results indicate that 14-3-3 proteins act as intracellular receptors for florigen in shoot apical cells, and offer new approaches to manipulate flowering in various crops and trees.

/pdf/14-3-3-proteins-act-as-intracellular-receptors-for-rice-hd3a-2geqyhzhiw.pdf

14-3-3 proteins act as intracellular receptors for rice Hd3a florigen

Development of series of gateway binary vectors, pGWBs, for realizing efficient construction of fusion genes for plant transformation

COPII vesicles mediate protein transport from ER to Golgi. Sec13 makes up lattice structure with Sec31 to form COPII vesicles. We analyzed expression of two Arabidopsis thaliana Sec13 homologs, AtSec13A and AtSec13B. AtSec13A was expressed in most parts of seedlings, while AtSec13B was partially expressed. Interaction of AtSec13A or AtSec13B with Sec31 homolog was demonstrated by bimolecular fluorescence complementation (BiFC).

Takeshi Hino

Papers

Development of series of gateway binary vectors, pGWBs, for realizing efficient construction of fusion genes for plant transformation

Improved Gateway binary vectors: high-performance vectors for creation of fusion constructs in transgenic analysis of plants.

Two Sec13p homologs, AtSec13A and AtSec13B, redundantly contribute to the formation of COPII transport vesicles in Arabidopsis thaliana.