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In order to obtain a green and efficient preparation process for carboxymethyl porous starch, carboxymethyl porous starch was prepared by mechanical activation solid phase etherification method, where enzymatically hydrolyzed porous cassava starch was used as raw material, sodium chloroacetate as etherifying agent, and sodium hydroxide as catalyst. Single-factor experiments were conducted to explore the effects of various factors on the degree of substitution (DS) of carboxymethyl porous starch, and the application of carboxymethyl porous starch in soy sauce was discussed. The results showed that the optimal process conditions for the preparation of carboxymethyl porous starch by mechanical activation and solid phase synthesis method were as follows: The molar ratio of porous starch to sodium chloroacetate was 1:1, the mass fraction of sodium hydroxide was 18.8%, the ball milling time was 1.5 h, and the reaction temperature was 50℃. Under these conditions, the highest DS of carboxymethyl porous starch obtained was up to 0.2532. Furthermore, the carboxymethylation reaction of porous starch was confirmed by infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). With the increase of DS of carboxymethyl porous starch, its cold water solubility, water absorption, and adsorption of lemon yellow increased. When DS was 0.2532, the cold water solubility of carboxymethyl porous starch reached 64.94%, the water absorption rate reached 180.73%, and the adsorption amount of lemon yellow reached 2.5086 mg·g−1. The powder soy sauce prepared by carboxymethyl porous starch has better solubility, lower moisture absorption, and higher content of amino acid nitrogen, and is closer to the original soy sauce compared to those prepared by cassava starch and porous starch. Therefore, the mechanical activation and solid phase etherification method can effectively prepare carboxymethyl porous starch, which is simple to operate, environmentally friendly, and highly substitutive, providing a scientific basis for the development and utilization of porous starch.

Fusarium crown rot (FCR) is a soilborne disease causing severe yield losses in many wheat-growing areas of the world. Diseased plants show browning and necrosis of roots and stems causing white heads at maturity. Little is known about the molecular processes employed by wheat roots to respond to the disease. We characterized morphological, transcriptional and hormonal changes in wheat seedling roots following challenge with Fusarium pseudograminearum (Fp), the main pathogen of FCR. The pathogen inhibited root development to various extents depending on plants’ resistance level. Many genes responsive to FCR infection in wheat roots were enriched in plant hormone pathways. The contents of compounds involved in biosynthesis and metabolism of jasmonic acid, salicylic acid, cytokinin and auxin were drastically changed in roots at five days post-inoculation. Presoaking seeds in methyl jasmonate for 24 h promoted FCR resistance, whereas presoaking with cytokinin 6-benzylaminopurine made plants more susceptible. Overexpression of TaOPR3, a gene involved in jasmonic acid biosynthesis, enhanced plant resistance as well as root and shoot growth during infection.

The sago starch was mechanically activated by a stirring-type ball mill as pretreatment, and the octenyl succinic acid starch ester was prepared by the esterification agent octenyl succinic anhydride. By adopting the degree of substitution (DS) as evaluating parameters, activation time, reaction time, the amount of octenyl succinic anhydride, reaction tem-perature, and pH on the esterification of sago starch were investigated respectively. The results indicated that mechanical activation significantly improved the esterification of sago starch octenyl succinic anhydride. Under the same reaction conditions, the degree of substitution and reaction efficiency of activated starch increased significantly. Through the orthogonal test, the optimal conditions for the preparation of activated 1.0 h starch ester could be determined: The reaction time was 2.0 h, the amount of octenyl succinic anhydride was 3%, the pH value was 8.0, and the temperature was 35 ℃. Under such conditions, the degree of substitution of starch ester prepared by esterification was 0.02294, the reaction efficiency was 98.01%. The results of the FTIR, XRD and SEM indicated that the FTIR spectrum of octenyl succinic anhydride sago starch showed new absorption peaks at 1570 cm−1 and 1712 cm−1, the crystallinity of starch decreased, and the surface of starch granules was damaged, with large holes appeared in the middle of starch granules. Thus the esterification reaction of sago starch was further confirmed. The emulsifying property of octenyl succnic anhydride modified strach with substitution degree of 0.02294 was 26.43%, and the emulsifying stability was 24.10%, which were superior to those of the original sago starch ester.

Wheat awns contribute to photosynthesis and grain production. In this study, an F2 population and F2:3 families from a cross between the awned line 7D12 and the Chinese awnless variety Shiyou 20 (SY20) were used to identify loci associated with awn length. Bulked-segregant RNA sequencing and linkage mapping identified a single dominant locus in a 0.3 cM interval on chromosome 5AL. Five genes were in the interval, including the recently cloned awn inhibitor B1. Although a single copy of the B1 gene was detected in 7D12, SY20 carried five copies of the gene. Increased copy number of B1 in SY20 enhanced gene expression. Based on sequence variation among the promoter regions of five B1 gene copies in SY20, two dominant markers were developed and found to cosegregate with B1 in a population of 931 wheat accessions. All 77 awnless accessions harbored sequence variations in the B1 promoter regions similar to those of SY20 and thus carried multiple copies of the gene, whereas 15 randomly selected awned wheats carried only one copy. These results suggest that an increase in copy number of the B1 gene is associated with inhibition of awn length.