Gene editing of the wheat homologs of TONNEAU1‐recruiting motif encoding gene affects grain shape and weight in wheat

Grain size and weight are important components of a suite of yield‐related traits in crops. Here, we showed that the CRISPR‐Cas9 gene editing of TaGW7, a homolog of rice OsGW7 encoding a TONNEAU1‐recruiting motif (TRM) protein, affects grain shape and weight in allohexaploid wheat. By editing the TaGW7 homoeologs in the B and D genomes, we showed that mutations in either of the two or both genomes increased the grain width and weight but reduced the grain length. The effect sizes of mutations in the TaGW7 gene homoeologs coincided with the relative levels of their expression in the B and D genomes. The effects of gene editing on grain morphology and weight traits were dosage dependent with the double‐copy mutant showing larger effect than the respective single copy mutants. The TaGW7‐centered gene co‐expression network indicated that this gene is involved in the pathways regulating cell division and organ growth, also confirmed by the cellular co‐localization of TaGW7 with α‐ and β‐tubulin proteins, the building blocks of microtubule arrays. The analyses of exome capture data in tetraploid domesticated and wild emmer, and hexaploid wheat revealed the loss of diversity around TaGW7‐associated with domestication selection, suggesting that TaGW7 is likely to play an important role in the evolution of yield component traits in wheat. Our study showed how integrating CRISPR‐Cas9 system with cross‐species comparison can help to uncover the function of a gene fixed in wheat for allelic variants targeted by domestication selection and select targets for engineering new gene variants for crop improvement.     

Different carbonic supplements induced changes of microflora in two types of compost teas and biocontrol efficiency against Pythium aphanidermatum

ABSTRACT

Considering the different carbonic source utilisation abilities of microbial species, we used six carbonic supplements to acclimate the microorganisms in two types of compost teas (named CT1 and CT2). The effects of the different carbonic supplements on the physicochemical and biological parameters of the acclimated microbial broth were investigated. The influence of these supplements on the biocontrol effect of the broth against cucumber damping off caused by Pythium aphanidermatum was also assessed. Results showed that treatment with glucose, sucrose, or starch reduced the pH and weakened the biocontrol effect of the acclimated microbial broth. The glucose treatment increased the population size of fungi and yeast. The chitin, cellulose, and wheat straw treatments significantly elevated the pH and electrical conductivity (P?<?0.05), increased the bacterial population size, and positively affected the biocontrol effect of the acclimated microbial broth. The glucose treatment had higher (75.3% and 79.4% for the CT1 and CT2, respectively) whereas the wheat straw treatment had lower (34.6% and 25.6% for the CT1 and CT2, respectively) disease incidence relative to the blank control (85.6%), bacterial population size (r?=?0.64 and 0.69) and number of colony types (r?=?0.82 and 0.76) highly correlated with the biocontrol effect of CT1 and CT2 while the reducing sugar content negatively correlated with the biocontrol effect (r?=??0.57 and ?0.86).     

TRPV5 and TRPV6 are expressed in placenta and bone tissues during pregnancy in mice

We investigated the dynamic expression of calcium transporters, TRPV5 and TRPV6, in placenta and bone to determine their role in maternal and fetal calcium balance during gestation. In placenta, TRPV5 was expressed predominantly in syncytiotrophoblasts of the labyrinthine zone, whereas TRPV6 was expressed in spongiotrophoblasts of the junction zone. In bone, the two transporters were found in osteoblasts, osteoclasts, cartilage and bone matrices. During the first half of gestation, TRPV5 and TRPV6 levels in bone were increased on pregnancy day (P) 0.5, then decreased on P3.5 followed by a slight increase on P6.5. During the second half of pregnancy, both the proteins and their mRNAs gradually increased from P9.5 to P15.5?P17.5 in both bone and placenta, followed at parturition by relatively high amounts in placenta, but markedly decreased amounts in bone. The expression pattern is likely related to the fetal and maternal calcium requirement during gestation, which may be regulated by estrogen and other hormones, because the fetal demand for calcium is greatest during the last few days of gestation for rats; maternal calcium metabolism is designed to meet the calcium needs of the fetus during this period. We found that TRPV5 and TRPV6 are involved in calcium transport in the placenta and bone, and therefore play a role in calcium homeostasis during embryonic and fetal development.     

Lipidomics characterization of the alterations of Trichoderma brevicompactum membrane glycerophospholipids during the fermentation phase

Journal of Industrial Microbiology & Biotechnology - The biological membrane lipid composition has been demonstrated to greatly influence the secretion of secondary metabolites. This study was...     

Role of lysine residues of the Magnaporthe oryzae effector AvrPiz-t in effector- and PAMP-triggered immunity

Magnaporthe oryzae is an important fungal pathogen of both rice and wheat. However, how M. oryzae effectors modulate plant immunity is not fully understood. Previous studies have shown that the M. oryzae effector AvrPiz-t targets the host ubiquitin-proteasome system to manipulate plant defence. In return, two rice ubiquitin E3 ligases, APIP6 and APIP10, ubiquitinate AvrPiz-t for degradation. To determine how lysine residues contribute to the stability and function of AvrPiz-t, we generated double (K1,2R-AvrPiz-t), triple (K1,2,3R-AvrPiz-t) and lysine-free (LF-AvrPiz-t) mutants by mutating lysines into arginines in AvrPiz-t. LF-AvrPiz-t showed the highest protein accumulation when transiently expressed in rice protoplasts. When co-expressed with APIP10 in Nicotiana benthamiana, LF-AvrPiz-t was more stable than AvrPiz-t and was less able to degrade APIP10. The avirulence of LF-AvrPiz-t on Piz-t:HA plants was less than that of AvrPiz-t, which led to resistance reduction and lower accumulation of the Piz-t:HA protein after inoculation with the LF-AvrPiz-t-carrying isolate. Chitin- and flg22-induced production of reactive oxygen species (ROS) was higher in LF-AvrPiz-t than in AvrPiz-t transgenic plants. In addition, LF-AvrPiz-t transgenic plants were less susceptible than AvrPiz-t transgenic plants to a virulent isolate. Furthermore, both AvrPiz-t and LF-AvrPiz-t interacted with OsRac1, but the suppression of OsRac1-mediated ROS generation by LF-AvrPiz-t was significantly lower than that by AvrPiz-t. Together, these results suggest that the lysine residues of AvrPiz-t are required for its avirulence and virulence functions in rice.