Sweet, grain, and dual-purpose sorghums differ in a number of important traits, including biomass production, total solutes in the stem juice, and sugar accumulation across the stem. Ten dual-purpose hybrids, two sweet genotypes, and two grain landraces of sorghums were characterized under temperate environmental conditions to determine their potential for bioethanol production. Five sorghum hybrids (Ganymed, Hannibal, Tarzan, Merlin, and Zerberus) performed better with respect to cane yield, juice yield, potential sugar, and ethanol yields compared to sweet and grain genotypes. While the sweet genotype KIT1 produced the highest sugar concentration in the stem, the lowest concentration was produced by the grain landrace Razinieh. The study showed that plant height, leaf number, leaf weight, cane yield, and juice yield were positively correlated with the sugar yield in fresh stalk. Sugar accumulation was higher in the central internodes of all genotypes. Clustering analysis showed that sweet genotypes are located more closely to dual-purpose hybrids than grain landraces. We discuss the results with respect to the potential of dual-purpose sorghum hybrids for bio-economy in Germany.

Phosphorus (P) is an essential macronutrient, playing a role in developmental and metabolic processes in plants. To understand the local and systemic responses of sorghum to inorganic phosphorus (Pi) starvation and the potential of straw and ash for reutilisation in agriculture, we compared two grain (Razinieh) and sweet (Della) sorghum varieties with respect to their morpho-physiological and molecular responses. We found that Pi starvation increased the elongation of primary roots, the formation of lateral roots, and the accumulation of anthocyanin. In Razinieh, lateral roots were promoted to a higher extent, correlated with a higher expression of SbPht1 phosphate transporters. Infrared spectra of straw from mature plants raised to maturity showed two prominent bands at 1371 and 2337 cm−1, which could be assigned to P-H(H2) stretching vibration in phosphine acid and phosphinothious acid, and their derivates, whose abundance correlated with phosphate uptake of the source plant and genotype (with a higher intensity in Razinieh). The ash generated from these straws stimulated the shoot elongation and root development of the rice seedlings, especially for the material derived from Razinieh raised under Pi starvation. In conclusion, sorghum growing on marginal lands has potential as a bio-economy alternative for mineral phosphorus recycling.

In a consequence of global warming, grapevine trunk diseases (GTDs) have become a pertinent problem to viticulture, because endophytic fungi can turn necrotrophic upon host stress killing the plant. In Neofusicoccum parvum Bt‐67, plant‐derived ferulic acid makes the fungus release Fusicoccin aglycone triggering plant cell death. Now, we show that the absence of ferulic acid lets the fungus secrete 4‐hydroxyphenylacetic acid (4‐HPA), mimicking the effect of auxins on grapevine defence and facilitating fungal spread. Using Vitis suspension cells, we dissected the mode of action of 4‐HPA during defence triggered by the bacterial cell‐death elicitor, harpin. Early responses (cytoskeletal remodelling and calcium influx) are inhibited, as well as the expression of Stilbene Synthase 27 and phytoalexin accumulation. In contrast to other auxins, 4‐HPA quells transcripts for the auxin conjugating GRETCHEN HAGEN 3. We suggest that 4‐HPA is a key component of the endophytic phase of N. parvum Bt‐67 preventing host cell death. Therefore, our study paves the way to understand how GTDs regulate their latent phase for successful colonisation, before turning necrotrophic and killing the vines.