RPT-Alibaba plays trademark card to protect lead as China's $8 bln e-commerce spree nears

BEIJING, Oct 30 (Reuters) - A trademark spat between Chinese e-commerce giant Alibaba Group Holding Ltd and rival JD.com flared into public view after JD published an Alibaba letter urging publishers to be careful about advertising in promotions for China's annual "Singles' Day" spree, the world's largest online shopping day.