Yaodan Zhang

β-glucan is an important component of crop cell walls, and its chemical structure is closely related to its physiological function. Among them, (1,3;1,4)-β-glucan (mixed-linkage β-glucan, MLGs) is a unique type of β-glucan in graminaceous crops. In recent years, the identification and functional analysis of the β-glucan synthesis gene family have provided key molecular targets for quality improvement of crops. This review systematically examines the classification, structure, and function of the β-glucan synthetic gene family, focusing on the regulatory network. This will lay a theoretical foundation for the further improvement of the β-glucan content in crops.

Crops often face light intensity fluctuations in natural settings. Intercropping is widely used to improve crop yield and resource utilization worldwide, but crops suffer from high-frequency and high-intensity light fluctuations due to mutual crop influence. Soybean is an important legume crop and is often intercropped with other crops, but little is known about soybean’s response to light fluctuation environments. Herein, three fluctuation frequencies (1, 10, and 20 min/cycle) were used to analyze soybean photosynthesis responses by measuring leaf growth, chlorophyll content, gas exchange, and electron transfer. Our data revealed that faster fluctuation frequencies led to the stronger suppression of soybean morphology and photosynthesis, with significant reductions of 31.31% and 21.58%, respectively. Damage to photosystems II (PSII) and I (PSI) also intensified, with significant decreases of 18.52% and 18.38% in their effective quantum yields Y(II) and Y(I). Additionally, increased fluctuation frequency exacerbated the consumption of the plastoquinone pool and linear electron flow but enhanced the cyclic electron flow across the thylakoid membrane and, thus, increased heat dissipation in PSII. Our findings indicate that an increased fluctuation frequency inflicted more severe damage on the soybean photosynthesis system. However, PSI-enhanced CEF improved NPQ and coordinated photoprotection to some extent.