The embedded design verification test of microwave circuit modules based on specific chips

In the Paper,the author introduces an embedded design verification test based on specific chips to solve the technical problems of microwave circuit test and fault diagnosis.The author explains embedded design of microwave circuit modules and approach of hardware design and software design,and finally verifies the embedded design of microwave circuit modules based on specific chips.

Ectopic expression of a male fertility gene,LOGL8,represses LOG and hinders panicle and ovule development

Grain number and seed-setting rate are components of crop yield.Cytokinin influences grain yield.However,emerging studies suggest that high cytokinin signals often lead to reduced branching or seed-setting rate,leading to reduced grain yield,although the mechanisms remain unclear.In this study,we identified and characterized the rice(Oryza sativa L.)gene LONELY GUY-LIKE 8(LOGL8),based on analysis of the LOGL8-pm(promoter mutant of LOGL8)mutant,which harbors a T-DNA insertion in the promoter of this gene.The mutation in LOGL8-pm causes ectopic hyperexpression of LOGL8 in inflorescence organs,resulting in plants with smaller panicles and defective ovules lacking archesporial cells and integuments.Knockout of LOGL8 caused pollen abortion,leading to a reduced seed-setting rate.LOGL8 encodes a putative cytokinin-activating enzyme.Our results showed that LOGL8 directly catalyzes the biosynthesis of bioactive cytokinins.Therefore,we propose that the ectopic expression of LOGL8 disrupts cytokinin spatiotemporal distribution and causes inhibition of LONELY GUY(LOG),which affects panicle branching and female organ development.These findings reveal the important role of LOGL8 in male development,and highlight the delicate balance of local cytokinin levels during panicle branching and female organ development.

A Robust CRISPR/Cas9 System for Convenient, High-Efficiency Multiplex Genome Editing in Monocot and Dicot Plants

CRISPR/Cas9 genome targeting systems have been applied to a variety of species. However, most CRISPR/Cas9 systems reported for plants can only modify one or a few target sites. Here, we report a robust CRISPR/Cas9 vector system, utilizing a plant codon optimized Cas9 gene, for convenient and high- efficiency multiplex genome editing in monocot and dicot plants. We designed PCR-based procedures to rapidly generate multiple sgRNA expression cassettes, which can be assembled into the binary CRISPR/ Cas9 vectors in one round of cloning by Golden Gate ligation or Gibson Assembly. With this system, we edi- ted 46 target sites in rice with an average 85.4% rate of mutation, mostly in biallelic and homozygous status. We reasoned that about 16% of the homozygous mutations in rice were generated through the non-homol- ogous end-joining mechanism followed by homologous recombination-based repair. We also obtained uni- form biallelic, heterozygous, homozygous, and chimeric mutations in Arabidopsis T1 plants. The targeted mutations in both rice and Arabidopsis were heritable. We provide examples of loss-of-function gene mu- tations in To rice and T1Arabidopsis plants by simultaneous targeting of multiple （up to eight） members of a gene family, multiple genes in a biosynthetic pathway, or multiple sites in a single gene. This system has provided a versatile toolbox for studying functions of multiple genes and gene families in plants for basic research and genetic improvement.

From Golden Rice to aSTARice:Bioengineering Astaxanthin Biosynthesis in Rice Endosperm

Carotenoids are important phytonutrients with antioxidant properties,and are widely used in foods and feedstuffs as Supplements.Astaxanthin,a red-colored ketocarotenoid,has strong antioxidant activity and thus can benefit human health.However,astaxanthin is not produced in most higher plants.Here we report the bioengineering of astaxanthin biosynthesis in rice endosperm by introducing four synthetic genes,sZmPSY1,sPaCrtl,sCrBKT,and sHpBHY,which encode the enzymes phytoene synthase,phytoene desaturase,β-carotene ketolase,and β-carotene hydroxylase,respectively.Transgneic overexpression of two (sZmPSY1 and sPaCrtl),three (sZmPSY1,sPaCrtl and sCrBKT),and all these four genes driven by rice endosperm-specific promoters established the Carotenoid/ketocarotenoid/astaxanthin biosynthetic pathways in the endosperm and thus resulted in various types of germplasm,from the yellow-grained β-caro- tene-enriched Golden Rice to orange-red-grained Canthaxanthin Rice and Astaxanthin Rice,respectively. Grains Of Astaxanthin Rice were enriched with astaxanthin in the endosperm and had higher antioxidant activity.These results proved that introduction of a minimal set of four transgenes enables de novo biosynthesis of astaxanthin in therice endosperm.This work provides a Successful example for synthetic biology in plants and biofortification in crops;the biofortified rice products generated by this study could be consumed as health-promoting foods and processed tO produce dietary supplements.

Development of ＂Purple Endosperm Rice＂ by Engineering Anthocyanin Biosynthesis in the Endosperm with a High-Efficiency Transgene Stacking System

Anthocyanins have high antioxidant activities, and engineering of anthocyanin biosynthesis in staple crops, such as rice （Oryza sativa L.）, could provide health-promoting foods for improving human health. However, engineering metabolic pathways for biofortification remains difficult, and previous attempts to engineer anthocyanin production in rice endosperm failed because of the sophisticated genetic regulatory network of its biosynthetic pathway. In this study, we developed a high-efficiency vector system for transgene stacking and used it to engineer anthocyanin biosynthesis in rice endosperm. We made a construct containing eight anthocyanin-related genes （two regulatory genes from maize and six structural genes from Coleus） driven by the endosperm-specific promoters,plus a selectable marker and a gene for marker excision. Transformation of rice with this construct generated a novel biofortified germplasm ＂Purple Endosperm Rice＂ （called ＂Zijingmi＂ in Chinese）, which has high anthocyanin contents and antioxidant activity in the endosperm. This anthocyanin production results from expression of the transgenes and the resulting activation （or enhancement） of expression of 13 endogenous anthocyanin biosynthesis genes that are silenced or expressed at low levels in wild-type rice endosperm. This study provides an efficient, versatile toolkit for transgene stacking and demonstrates its use for successful engineering of a sophisticated biological pathway, suggesting the potential utility of this toolkit for synthetic biology and improvement of agronomic traits in plants.

Shortened snRNA promoters for efficient CRISPR/Cas-based multiplex genome editing in monocot plants

Dear Editor,CRISPR(clustered regularly interspaced short palindromic repeats)/Cas genome editing is a powerful tool for introducing specific mutations in organisms including plants.The system is composed of a nuclease such as Cas9 or Cas12a and an engineered single-guide RNA(sgRNA)incorporating a target sequence(Li et al.,2019).A Cas9/sgRNA complex recognizes its target site in the genome,resulting in a mutation at that site.